Question

To fill a swimming pool two pipes are used if the pipe of larger diameter used for 4 hour and the pipe of a smaller diameter for 9 hours only half of the pool can be filled .find how much long it would take for each pipe to fill the pool separately if the pool of a smaller diameter takes 10 hour more than the pool of larger diameter to fill the pool? (2015 cbse)




this question is from Rd sharma book page no. 8.74.
I want full solution plz

Answer 1

let x hour be the time taken by larger pipe to fill the tank
So in one hour it would fill 1/x part of the tank
Same way as y hour is needed for smaller pipe then in one hour it would fill 1/y part
Now it is given y - x = 10
==> y = x + 10
Also 4 *1/x + 9 *1/y = 1/2
Now plug y = x + 10 in this
We get 4/x + 9/(x+10) = 1/2
Rearranging we get x^2 - 16x - 80 = 0
OR (x -20)(x+4) = 0
Hence x = 20 h
And y = 30 h
So larger dia pipe would fill in 20 h and smaller dia pipe would fill the pool in 30 h

Answer 2

Answer:time taken by larger pipe=

Explanation: