SOLUTION: Two buckets are used to fill a large bathtub with water. Bucket A is larger and by itself it can fill the bathtub in 20 minutes. Bucket B is smaller and by itself it can fill the b

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Two buckets are used to fill a large bathtub with water. Bucket A is larger and by itself it can fill the bathtub in 20 minutes. Bucket B is smaller and by itself it can fill the b      Log On


   

Question 985095: Two buckets are used to fill a large bathtub with water. Bucket A is larger and by itself it can fill the bathtub in 20 minutes. Bucket B is smaller and by itself it can fill the bathtub in 50 minutes. If the two buckets are used together how much time(minutes) does it take to fill the bathtub?
Answer by ikleyn(52754) About Me  (Show Source):
You can put this solution on YOUR website!
First bucket fills the bathtub in  20  minutes.  Hence,  it fills  1%2F20  of the bathtub volume per minute.

The second bucket fills the bathtub in  50  minutes.  Hence,  it fills  1%2F50  of the bathtub volume per minute.

If two buckets are used,  they fill  1%2F20 + 1%2F50 = +5%2F100+%2B+2%2F100 = 7%2F100  of the bathtub volume each minute.

Hence,  it will take  100%2F7 = 142%2F7  minutes to fill the bathtub using two buckets.


This problem is the  "rate-of-work"  problem on joint work.
For more of these problems see my lessons in this site
    - Using Fractions to solve word problems on joint work,
    - Using quadratic equations to solve word problems on joint work,
    - Solving rate of work problem by reducing to a system of linear equations.