# Any mathematicians out there??

max888
Posts:

**206**
Does anybody want to have a crack at an algebraic puzzle, I have not got very far i.e. nowhere at all.

'

Thanks,

Max

'

*A small swimming pool can be filled with two pipes in 3 hours. If the larger pipe alone takes 8 hours less than the smaller pipe to fill the pool, find the time in which it will be filled by each pipe singly.*'Thanks,

Max

0

## Posts

1,287Large pipe must be more than 3 hours, so small pipe must be more than 11.

And I can't get further than that.

I feel it, when I sorrow most;

'Tis better to have loved and lost;

Than never to have loved at all."

Alfred Tennyson

206Max

http://dottyjumper.posterous.com/

http://twitter.com/#!/MaxGloger

1,287PMed.

I feel it, when I sorrow most;

'Tis better to have loved and lost;

Than never to have loved at all."

Alfred Tennyson

25,894Make the pool 300 units in size. Make the rates of the two pipes X and Y units per hour. (Y is the faster)

Therefore 300/3=X+Y. So X=100-Y

And 300/X - 8 = 300/Y

Multiply by X and Y: 300Y -8XY= 300X

Substitute X: 300Y -800Y +8Y^2 = 30,000 -300Y

Simplify: Y^2 -25Y -3,750 = 0

Solve : Y= 75 so X=25

Therefore times are 300/75 and 300/25. 8 hours and 4 hours.

1,278:shock: :shock: :? :? :oops: :oops:

I is fick :oops:

FCN3

http://img87.yfrog.com/img87/336/mycubeb.jpg

http://lonelymiddlesomethingguy.blogspot.com/

1,287Pool Full = 1 (arbitrarily)

large pipe time alone = x

small pipe time alone = y,

y = x+8

3 hours is the total time so you divide it by the individual pipes to get their contribution.

(3/x+8 ) + (3/x) = 1

times by x(x+8 ) gives

3x + 3(x+8 )l = x(x+8 )

3x + 3x+24= x^2 + 8x

(-6x, - 24) equals

0 = x^2 + 8x - 6x - 24

0 = x^2 + 2x - 24

0 = (x-4)(x+6)

only positive answer is that x (large pipe) = 4

therefore y (small pipe) = x+8 = 12.

I feel it, when I sorrow most;

'Tis better to have loved and lost;

Than never to have loved at all."

Alfred Tennyson

25,894The maths is essentially the same though.

3,513206http://dottyjumper.posterous.com/

http://twitter.com/#!/MaxGloger

5,1824613,782Winter

Racey

Special Favourite

If in doubt, blame Wiggle.

1,261north west of england.

1,287Pool filled in 3 hours (originally), than a leak appeared!!

If full, the pool completely empties in 5 hours through the annoying leak.

How long does the pool take to fill, bearing in mind the annoying leak?

I feel it, when I sorrow most;

'Tis better to have loved and lost;

Than never to have loved at all."

Alfred Tennyson

42Edit - no, 7.5 hours ...

206It's not technically homework, just a small pack to stop me forgetting everything over the holidays!

http://dottyjumper.posterous.com/

http://twitter.com/#!/MaxGloger

3,695560By the way... can someone explain in layman's language how binary works? In 1st year at Secondary I was a lazy git so got kicked out of the top class into the next one down - they had already done binary, we hadn't, so I missed it. There was a question on my O-level paper using binary and I couldn't even attempt it. Ta.

25,894We all show thickness in different ways. I didn't realise it was a bank holiday until they mentioned it on the radio at 8.30 on Monday morning. Now that's thick.

750This looks interesting...

6,553The above post may contain traces of sarcasm or/and bullsh*t.

1,261north west of england.

206http://dottyjumper.posterous.com/

http://twitter.com/#!/MaxGloger

1,329206http://dottyjumper.posterous.com/

http://twitter.com/#!/MaxGloger

7,674206http://dottyjumper.posterous.com/

http://twitter.com/#!/MaxGloger

1,3293,461Good to know that 31 years after leaving school, and having to learn sufficient algebra to pass various science exams, that I still don't understand it, I still can't do it and, what's more, during my entire working life I've never needed to.

Bob

1,2872nd one is right.

I feel it, when I sorrow most;

'Tis better to have loved and lost;

Than never to have loved at all."

Alfred Tennyson