Algebra II Question

Question

A pool can be filled by one pipe in 3

hours and by a second pipe in 5

hours.

How long will it take using both pipes to fill the​ pool?

Answer: It will

take about ? hours to fill the pool using both pipes.

Answer 1

The first pipe can be thought of as filling 1/3 of a pool per hour, and the second can be thought of as filling 1/5 of a pool per hour. Thus, together they fill 1/3+1/5 = 8/15 of a pool per hour.

looking at the units (pool/hour) we see that flipping the fraction gives us the number of hours per pool. So the answer is 15/8 hours per pool.

Answer 2

t represents the time it takes both to fill the pool

(t / 3) + (t / 5) = 1

Can you solve for t and answer?