Question

It takes 24 hours to fill a swimming pool using two pipes.if the pipe of larger diameter is used for 8 hours and the pipe of the smaller diameter is used for 18 hours .only half of the pool his filled. How long would each pipe take to fill the swimming pool.

Answer 1

hope so it will help u a lot....... 
the solution would be like this:-

let the time taken by the 1 pipe be x hours and let the time taken by the 2 pipe be y hours.

& the in 1 hour the 1 pipe can fill it=1/x

the in 1 hour the 2 pipe can fill it=1/y

1/x +1/y = 1/12           -1

4/x = 9/9 =1/2             -2

let 1/x be a and 1/y be b.

a+b= 1/12             -3

4a + 9b = 1/2         -4

multiply 3 by 4 and then subtract 5 and 6.

4a +4b=1/3       -5

4a + 9b = 1/2     -6

we get, b=1/30

y=30.

sustituting the value of y in eq. 3

a+1/30=1/12

x=20.

Hence the 1 pipe would take 20hours and the 2 pipe would take 30 hours.

Answer 2

see half 1/2 the bigger pipe =8×2=16