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# Thread: Math People - Help!

1. Matt Markus Guest

## Math People - Help!

At an interview, I was asked to come with an equation for the following
scenario:

Right now, a mother is 4 times as old as her daughter. In 20 years, the
mother will be only twice as old as the daughter. How old are both of them
right now?

I suck at math, and consequently choked on the question. Can someone steer
me right?

Thanks!

2. Geert Marttin Guest

## Re: Math People - Help!

"Matt Markus" <matt_markus@hotmail.com> wrote in message
news:3a425469\$1@news.devx.com...
> At an interview, I was asked to come with an equation for the following
> scenario:
>
> Right now, a mother is 4 times as old as her daughter. In 20 years, the
> mother will be only twice as old as the daughter. How old are both of them
> right now?

Motheraughter
Now 40:10
Then 60:30

Later...

Geert Marttin

3. mrfelis Guest

## Re: Math People - Help!

The equations come directly from the words.

Mother = 4 X Daughter

Mother + 20 = 2 X (Daughter + 20)

--
~~~
!ti timda I ,KO
..em deppals nocaeB sivaM
!draH
~~
C'Ya,
mrfelis@yahoo!com
Matt Markus <matt_markus@hotmail.com> wrote in message
news:3a425469\$1@news.devx.com...
> At an interview, I was asked to come with an equation for the following
> scenario:
>
> Right now, a mother is 4 times as old as her daughter. In 20 years, the
> mother will be only twice as old as the daughter. How old are both of them
> right now?
>
> I suck at math, and consequently choked on the question. Can someone steer
> me right?
>
> Thanks!
>
>

4. NSiddiqui@fcleasing.com Guest

## Re: Math People - Help!

<br><font size=1 face="sans-serif">Daghter : Mother</font>
<br><font size=1 face="sans-serif">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;X &nbsp; &nbsp; : &nbsp; &nbsp; &nbsp;Y</font>
<br>
<br><font size=1 face="sans-serif">4X &nbsp; &nbsp; &nbsp; &nbsp;= &nbsp; &nbsp; &nbsp; &nbsp;Y &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;'Now</font>
<br><font size=1 face="sans-serif">2(X+20) &nbsp; &nbsp; &nbsp; &nbsp;= &nbsp; &nbsp; &nbsp; &nbsp;Y+20 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;'20 Years later</font>
<br><font size=1 face="sans-serif">-------------------------------------------</font>
<br><font size=1 face="sans-serif">2X-40 &nbsp; &nbsp; &nbsp; &nbsp;= &nbsp; &nbsp; &nbsp; &nbsp; -20 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;'Subtracting the two equations</font>
<br><font size=1 face="sans-serif">=&gt; &nbsp; X &nbsp; &nbsp; &nbsp; &nbsp;= &nbsp; &nbsp; &nbsp; &nbsp;10 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;'Daughter's age</font>
<br><font size=1 face="sans-serif">=&gt; &nbsp; Y &nbsp; &nbsp; &nbsp; &nbsp;= &nbsp; &nbsp; &nbsp; &nbsp;4*10 = 40 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;'Mother's age</font>

5. Matt Markus Guest

## Re: Math People - Help!

Hi Geert,

"Geert Marttin" <G.Marttin@Chello.nl> wrote in message
news:3a4256d9@news.devx.com...
> "Matt Markus" <matt_markus@hotmail.com> wrote in message
> news:3a425469\$1@news.devx.com...
> > At an interview, I was asked to come with an equation for the following
> > scenario:
> >
> > Right now, a mother is 4 times as old as her daughter. In 20 years, the
> > mother will be only twice as old as the daughter. How old are both of

them
> > right now?

>
> Motheraughter
> Now 40:10
> Then 60:30
>
> Later...
>
> Geert Marttin
>
>

Thanks for the answer, but can you tell me the equation to arrive at that

6. Matt Markus Guest

## Re: Math People - Help!

Hi --
<NSiddiqui@fcleasing.com> wrote in message news:3a425e39@news.devx.com...

Daghter : Mother
X : Y

4X = Y 'Now
2(X+20) = Y+20 '20 Years later
-------------------------------------------
2X-40 = -20 'Subtracting the two equations
=> X = 10 'Daughter's age
=> Y = 4*10 = 40 'Mother's age

Can you explain, in plain words, what that is doing? I really haven't had any algebra classes, and, as a result, don't understand that too well.

7. Arthur Wood Guest

## Re: Math People - Help!

Matt,

express the two parts of the problem, in numerical format:

1)
Mother's age = 4 * Daughter's age

2)
Mother's age + 20 = 2 * (Daughter's age + 20)
which is the same as
Mother's age + 20 = 2 * Daughter's age + 40

but you know from part 1) then

Mother's age = 4 * Daughter's age

so you can then epress 2) as

4 * Daughter's Age + 20 = 2 * Daughter's age + 40

which then becomes, by subtracting 20 from both sides:

4 * Daughter's Age = 2 * Daughter's age + 20

now subtract (2 * Daughter's age) from both sides to get:

2 * Daughter's Age = 20

now divide both sides by 2 to get

Daughter's Age = 10

and then by 1) Mother's Age = 4 * Daughter's Age = 4* 10 = 40

That is what you set out to show.

But this is a Visual Basic Programming news group, not a basic Algebra support
group.

Arthur Wood

"Matt Markus" <matt_markus@hotmail.com> wrote:
>This is a multi-part message in MIME format.
>
>------=_NextPart_000_0062_01C06B5E.BC555260
>Content-Type: text/plain;
> charset="iso-8859-1"
>Content-Transfer-Encoding: quoted-printable
>
>Hi --
> <NSiddiqui@fcleasing.com> wrote in message =
>news:3a425e39@news.devx.com...
>
> Daghter : Mother=20
> X : Y=20
>
> 4X =3D Y 'Now=20
> 2(X+20) =3D Y+20 '20 Years later=20
> -------------------------------------------=20
> 2X-40 =3D -20 'Subtracting the =
>two equations=20
> =3D> X =3D 10 'Daughter's age=20
> =3D> Y =3D 4*10 =3D 40 =
>'Mother's age
>
>
> Can you explain, in plain words, what that is doing? I really haven't

=
>had any algebra classes, and, as a result, don't understand that too =
>well.
>
>
>
>
>------=_NextPart_000_0062_01C06B5E.BC555260
>Content-Type: text/html;
> charset="iso-8859-1"
>Content-Transfer-Encoding: quoted-printable
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><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
><META http-equiv=3DContent-Type content=3D"text/html; =
>charset=3Diso-8859-1">
><META content=3D"MSHTML 5.50.4134.600" name=3DGENERATOR>
><STYLE></STYLE>
><BODY bgColor=3D#ffffff>
><DIV><FONT face=3DArial size=3D2>Hi --</FONT></DIV>
><BLOCKQUOTE=20
>BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
> <DIV><<A=20
> =
>href=3D"mailto:NSiddiqui@fcleasing.com">NSiddiqui@fcleasing.com</A>> =
>wrote in=20
> message <A=20
> =
>href=3D"news:3a425e39@news.devx.com">news:3a425e39@news.devx.com</A>...</=
>DIV>
> <DIV><BR><FONT face=3Dsans-serif size=3D1>Daghter : Mother</FONT> =
><BR><FONT=20
> face=3Dsans-serif size=3D1> X =
> :=20
> Y</FONT> <BR><BR><FONT face=3Dsans-serif =
>size=3D1>4X =20
> =3D Y =
> =20
> 'Now</FONT> =
><BR><FONT=20
> face=3Dsans-serif size=3D1>2(X+20) =3D =
> =20
> Y+20 =
> =20
> '20 Years later</FONT> <BR><FONT =
>face=3Dsans-serif=20
> size=3D1>-------------------------------------------</FONT> <BR><FONT=20
> face=3Dsans-serif size=3D1>2X-40 =3D =
> =20
> -20 =
> =20
> 'Subtracting the two equations</FONT> <BR><FONT=20
> face=3Dsans-serif size=3D1>=3D> X =
> =3D =20
> 10 =
> =20
> 'Daughter's age</FONT> <BR><FONT =
>face=3Dsans-serif=20
> size=3D1>=3D> Y =3D =
> =20
> 4*10 =3D 40 =
> =20
> 'Mother's age</FONT></DIV>
> <DIV><FONT face=3D"Lucida Sans Unicode" size=3D1></FONT> </DIV>
> <DIV><FONT face=3D"Lucida Sans Unicode" size=3D1></FONT> </DIV>
> <DIV><FONT face=3D"Lucida Sans Unicode" size=3D1>Can you explain, in =
>plain words,=20
> what that is doing? I really haven't had any algebra classes, and, as

=
>a=20
> result, don't understand that too well.</FONT></DIV>
> <DIV><FONT face=3D"Lucida Sans Unicode" size=3D1></FONT> </DIV>
> <DIV><FONT face=3D"Lucida Sans Unicode" size=3D1></FONT> </DIV>
> <DIV><FONT face=3D"Lucida Sans Unicode"=20
>size=3D1></FONT> </DIV></BLOCKQUOTE></BODY></HTML>
>
>------=_NextPart_000_0062_01C06B5E.BC555260--
>

8. Matt Markus Guest

## Re: Math People - Help!

Hi Arthur --

"Arthur Wood" <arthurw189@aol.com> wrote in message
news:3a4264c6@news.devx.com...
> That is what you set out to show.
>
> But this is a Visual Basic Programming news group, not a basic Algebra

support
> group.
>
> Arthur Wood
>

I know, and I appreciate your explanation. But it *was* asked in an
interview for a VB Programmer position. Do you, or anyone here, think that's
a relevent, or even appropriate question for such an interview?

Thanks again.

9. Matthew Solnit Guest

## Re: Math People - Help!

"Matt Markus" <matt_markus@hotmail.com> wrote in message
news:3a426630\$1@news.devx.com...
> Hi Arthur --
>
> "Arthur Wood" <arthurw189@aol.com> wrote in message
> news:3a4264c6@news.devx.com...
> > That is what you set out to show.
> >
> > But this is a Visual Basic Programming news group, not a basic Algebra

> support
> > group.
> >
> > Arthur Wood
> >

>
> I know, and I appreciate your explanation. But it *was* asked in an
> interview for a VB Programmer position. Do you, or anyone here, think that's
> a relevent, or even appropriate question for such an interview?

Of course it is. Professional computer programming requires a certain level of
mathematics, and this is +very+ beginner's algebra. They were testing what kind
of educational background you have. I bet they would have asked this question
no matter what programming language the job required.

You can find plenty of jobs without doing algebra. But if you want to really
learn the stuff, you are going to have to devote some time and effort. You
won't learn how to solve problems like that in a newsgroup. I would recommend
community college, or at least a good book and some tutoring.

-- Matthew Solnit

10. Michael Culley Guest

## Re: Math People - Help!

Matthew,

Not knowing this level of algebra would be a huge problem in a programming
job. I would not hire someone who could not answer this question. In fact
I might start asking this question in future.

Michael Culley

"Matthew Solnit" <msolnit@nospam.yahoo-com> wrote:
>"Matt Markus" <matt_markus@hotmail.com> wrote in message
>news:3a426630\$1@news.devx.com...
>> Hi Arthur --
>>
>> "Arthur Wood" <arthurw189@aol.com> wrote in message
>> news:3a4264c6@news.devx.com...
>> > That is what you set out to show.
>> >
>> > But this is a Visual Basic Programming news group, not a basic Algebra

>> support
>> > group.
>> >
>> > Arthur Wood
>> >

>>
>> I know, and I appreciate your explanation. But it *was* asked in an
>> interview for a VB Programmer position. Do you, or anyone here, think

that's
>> a relevent, or even appropriate question for such an interview?

>
>Of course it is. Professional computer programming requires a certain level

of
>mathematics, and this is +very+ beginner's algebra. They were testing what

kind
>of educational background you have. I bet they would have asked this question
>no matter what programming language the job required.
>
>You can find plenty of jobs without doing algebra. But if you want to really
>learn the stuff, you are going to have to devote some time and effort.

You
>won't learn how to solve problems like that in a newsgroup. I would recommend
>community college, or at least a good book and some tutoring.
>
>-- Matthew Solnit
>
>

11. Ian Post Guest

## Re: Math People - Help!

<matt>
> I know, and I appreciate your explanation. But it *was* asked in an
> interview for a VB Programmer position. Do you, or anyone here, think

that's
> a relevent, or even appropriate question for such an interview?

</matt>

Extremely relevant. Programming requires problem solving, conversion of a
real-world situation into an algorythm. ****, that's not what programming
requires, that's what it is.

Over on the Off Ramp, another similar question from an interview was posted
(By Nancy Folsom, I think)... it gets you on math and logic:

Q: Statistically, if 1 1/2 chickens lay 1 1/2 eggs in 1 1/2 days, how many
days does it take one chicken to lay a dozen eggs?

If I ever interview programmers again (currently consulting freelance), I
will definately use this one.

Ian

12. Travis Hall Guest

## Re: Math People - Help!

"Matt Markus" <matt_markus@hotmail.com> wrote:
>
>I know, and I appreciate your explanation. But it *was* asked in an
>interview for a VB Programmer position. Do you, or anyone here, think that's
>a relevent, or even appropriate question for such an interview?

That question was really a test of your general mathematical ability. Mathematics
is relevant to almost any professional job, and there aren't really that
many non-professional jobs which don't use it at all. Were I an employer,
I would be hesitant to hire a secretary who couldn't solve that problem,
let alone a programmer.

My initial tertiary education was in the field of mathematics. I turned to
programming when I figured out that I didn't really want to be a mathematician.
In the time since, I have been amazed at how often the techniques I learned
during my studies in maths have applied to my programming work. Apart from
the obvious need to solve actual math problems as a part of programming,
the problem solving techniques that are naturally acquired in the learning
of mathematics have made me a much better programmer and analyst than I otherwise
would be.

Incidentally, until I became a programmer, I supported myself by tutoring.
As an experienced tutor, I would strongly advise you to consider undertaking
some studies to improve your maths skills, and perhaps getting some help
with it. I used to tutor kids who could solve that problem with ease, but
who were still failing their maths classes.

Travis Hall

13. Eric D. Burdo Guest

## Re: Math People - Help!

Hehe... I remember that one. It was in an old Role playing book I had. You had to answer
the question before you could get this guy to help you out...

Kinda fun...

--

Eric D. Burdo, Red-Leif International
VB Programmer and Consultant
<http://www.redleif.com/vb>

"Ian Post" <SpamFree@TheWay.ToBe> wrote in message news:3a428d8f@news.devx.com...
> <matt>
> > I know, and I appreciate your explanation. But it *was* asked in an
> > interview for a VB Programmer position. Do you, or anyone here, think

> that's
> > a relevent, or even appropriate question for such an interview?

> </matt>
>
> Extremely relevant. Programming requires problem solving, conversion of a
> real-world situation into an algorythm. ****, that's not what programming
> requires, that's what it is.
>
> Over on the Off Ramp, another similar question from an interview was posted
> (By Nancy Folsom, I think)... it gets you on math and logic:
>
> Q: Statistically, if 1 1/2 chickens lay 1 1/2 eggs in 1 1/2 days, how many
> days does it take one chicken to lay a dozen eggs?
>
> If I ever interview programmers again (currently consulting freelance), I
> will definately use this one.
>
> Ian
>
>

14. Matt Markus Guest

## Re: Math People - Help!

"Eric D. Burdo" <vbtips@redleif.com> wrote in message
news:3a435958\$1@news.devx.com...
> Hehe... I remember that one. It was in an old Role playing book I had.

> the question before you could get this guy to help you out...
>
> Kinda fun...
>
> --
>
> Eric D. Burdo, Red-Leif International
> VB Programmer and Consultant
> <http://www.redleif.com/vb>
>
> *** Please reply to the newsgroup so all can benefit. ***
>
>
> "Ian Post" <SpamFree@TheWay.ToBe> wrote in message

news:3a428d8f@news.devx.com...
> > <matt>
> > > I know, and I appreciate your explanation. But it *was* asked in an
> > > interview for a VB Programmer position. Do you, or anyone here, think

> > that's
> > > a relevent, or even appropriate question for such an interview?

> > </matt>
> >
> > Extremely relevant. Programming requires problem solving, conversion of

a
> > real-world situation into an algorythm. ****, that's not what

programming
> > requires, that's what it is.
> >
> > Over on the Off Ramp, another similar question from an interview was

posted
> > (By Nancy Folsom, I think)... it gets you on math and logic:
> >
> > Q: Statistically, if 1 1/2 chickens lay 1 1/2 eggs in 1 1/2 days, how

many
> > days does it take one chicken to lay a dozen eggs?
> >
> > If I ever interview programmers again (currently consulting freelance),

I
> > will definately use this one.
> >
> > Ian
> >
> >

>
>

Interesting notions for a presumably "logical" group of programmers...

So let me get this straight, for the record: "one *needs* to be know algebra
in order to be a productive VB Programmer"? That's insane. I have living
examples here, all around me, of people who are proficient programmers but
could *not* solve that problem; either because they never had algebra in the
first place, or have just forgotten it. In fact, one of the best coders I
know couldn't solve that problem. So explain that paradox, oh supreme
logical ones.

I actually kind of regret bringing this up, now that some of you are going
to force potential employees to abandon their focus on programming to take
some crash course in Algebra at the local community college, not because
they need to be a better programmer, but merely to get through the
interview!?! Why don't you ask them to write a little application, or even
just a procedure instead? Have them code something for God's sake!

Yeah, next time I interview a developer I'm going to bust out the legos and
tell them to build me a space station. Hey, that's requires problem solving!

15. Ian Post Guest

## Re: Math People - Help!

Matt:

> Interesting notions for a presumably "logical" group of programmers...
>
> So let me get this straight, for the record: "one *needs* to be know

algebra
> in order to be a productive VB Programmer"?

If you are doing any coding of logic and problem solving (90% of
programming), yes. If all you are doing is UI design and database
read-write, then you can get by without it, but I'd never hire someone that
limited.

> That's insane. I have living
> examples here, all around me, of people who are proficient programmers but
> could *not* solve that problem; either because they never had algebra in

the
> first place, or have just forgotten it. In fact, one of the best coders I
> know couldn't solve that problem. So explain that paradox, oh supreme
> logical ones.

You don't know very many good coders, IMHO, if the best one you know
couldn't solve the chicken problem. From my experience, the best coders I
know actually enjoy math and problem solving to the point where Dr. Eco's
problems are too easy for them.

> I actually kind of regret bringing this up, now that some of you are going
> to force potential employees to abandon their focus on programming to take
> some crash course in Algebra at the local community college, not because
> they need to be a better programmer, but merely to get through the
> interview!?! Why don't you ask them to write a little application, or

even
> just a procedure instead? Have them code something for God's sake!

OK, here's one for you: Write an application to solve the chicken problem.
How would you do that if you do not know how yourself? Or to be more
general: Write an app to provide cost estimating on construction projects,
giving the user options based on current prices of product and the most
cost-effective manner of completing the project. How could you do that
without these types of basic math skills?

As an aside, we've gone a little off the topic of VB specific issues here.
This conversation might be more appropriately held in the off ramp
(subscribe to off.ramp on news.devx.com). Up to you, of course.

Ian

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