Question

two pipes A and B can fill a cistern in 2/5 hr. and 8/15 hr. respectively. If both the pipes are opened simultaneously, after how much time should pipe B be closed so that the cistern is full in 18 minutes​

Answer 1

the boys received a fast response to

Answer 2

Answer:

240 min

Step-by-step explanation:

Correct option is

A

240

Let N be closed after x hrs 

Then from the question, we have

x(121+161)+(9−x)121=1

⇒x  = 16×123

⇒x = 4 hrs = 240 minutes