Question

A tank can be fully filled with water using a pipe that fills 20 litres in a minute . A bigger pipe that can fill 25 litres in a minute will take one minute less to fill the same tank . How many minutes does the smaller pipe take to fill the tank ?​

Answer 1

Answer: 5 minutes

Step-by-step explanation:

rate of filling for smaller pipe = 20L/1 minute

rate of filling for bigger pipe = 25L/1 minute

Let,

the small pipe fill the tank in x minutes

Then, ATQ

the big pipe will fill the tank in x-1 minutes

therefore,

20/1*x = 25/1*(x-1)

solving the above equation we get

20x = 25x - 25

20x - 25x = -25

-5x = -25

x = 25/5 (- sign on both sides get cancelled so it is positive)

x = 5

therefore 5 minutes.