Question

one top can fill a cistern in 2 hours and another can empty the
cistern in 3 hours. How long will they take to fill the cistern of both
the taps are opened?​

Answer 1

Answer:

6 hrs

Step-by-step explanation:

a will require 2 hrs to fill cistern

b will require 3 hrs to fill cistern

no. of hrs to fil cistern when both the taps opened=n

. first cistern tap be a

let another cistern tap be b

$\frac{1}{n } = \frac{1}{a} + \frac{1}{b}$

here,

$\frac{1}{a} = \frac{1}{2} and \: \frac{1}{b } = \frac{1}{ - 3}$

so,

$\frac{1}{2} + \frac{1}{ - 3 } = \frac{1}{2} - \frac{1}{3} = \frac{1}{6}$

so time require to fill cistern is 6 hrs