Question

A pool can be filled by one pipe in 6 hours and by a second in 12 hours . How long will it take using both pipes to fill the pool?

Answer 1

Answer:

4 hours

Step-by-step explanation:

Part of the pool filled by first pipe in an hour = 1/6

Part of the pool filled by second pipe in an hour = 1/12

Part of the pool filled by first pipe and second pipe in an hour = 1/6 +1/12

             $=\frac{1*2}{6*2}+\frac{1}{12}\\= \frac{2}{12}+\frac{1}{12}\\\\=\frac{3}{12}\\\\=\frac{1}{4}$

Time taken by both the pipes to fill the pool = 4 hours

Answer 2

One pipe = 1/6 of the pool in one hour
Second pipe = 1/12 of the pool in one hour
Let x be the time
Make them equal to 1 (total of pool)
1/6(x) + 1/12(x) = 1
Make non fraction by multiplying by 12
2x + 1x = 12
3x = 12, x = 4
It would take 4 hours