Two pipes A and B can fill a tank in 24 minutes and 32 minutes respectively. If both the pipes are
opened simultaneously, after how much time should B be closed so that the tank is full in 18
minutes?
Pick:
A) 7 minute	B) 9 minute	C) 10 minute	D) 8 minute	E) 11 minute

Rationale: pipe a will work for 18 minutes . suppose pipe b is closed after x minutes than we have 18 / 24 + x / 32 = 1 x = 8 minute . answer : d
Answer: D