Filling a tank

[pat666]

1. The problem statement, all variables and given/known data

"A tank can be filled in 6 hours using 2 pipes. The larger pipe alone would fill it 5 hours sooner than the smaller pipe alone. How long would each pipe alone take?"

2. Relevant equations

I know it involves a quadratic not sure on the rest... I cant see how to do with a quadratic i mean.

3. The attempt at a solution
assume a is the big pipe and b is the small
A+B=6
A=B+5 solved them to get a=11/2hours and b=1/2, i can see thats not right. i said that a was the bigger one and my answer says that its not????

[Aceterp]

1. The problem statement, all variables and given/known data

"A tank can be filled in 6 hours using 2 pipes. The larger pipe alone would fill it 5 hours sooner than the smaller pipe alone. How long would each pipe alone take?"

2. Relevant equations

I know it involves a quadratic not sure on the rest... I cant see how to do with a quadratic i mean.

3. The attempt at a solution
assume a is the big pipe and b is the small
A+B=6
A=B+5 solved them to get a=11/2hours and b=1/2, i can see thats not right. i said that a was the bigger one and my answer says that its not????


This website may help you

http://www.algebra.com/algebra/homework/Rate-of-work-word-problems/HOW-TO-Solve-Rate-of-Work-Problems.lesson


So using the the equation form the website you get

1/a + 1/a+5 = 1/6

This simplifies to

(2a+5)/a(a+5) = 1/6

which simplifies down to the quadratic a^2 – 7a -30 = 0

[pat666]

ok thanks