Answer:
1.56 hours
Step-by-step explanation:
Given,
Rate of first inlet
= 1 pool per 7 hours
= (1/7) pool per hour
Rate of 2nd inlet
= 1 pool in 2 hours
= (1/2) pool per hour
Combined rate = Rate of 1st inlet + Rate of 2nd inlet
= 1/7 + 1/2
= 2/14 + 7/14
= 9/14 pool per hour
taking the inverse of the combined rate gives the time it takes to fill the pool in hours. Hence,
Time for Both pipes to fill the pool = 1 / (9/14) = 14/9 = 1.56 hours