Two pipes 1 and 2 can fill a tank in 2.5 hours and 4 hours respectively. If both pipes are opened together, then after what time should 1 be closed so that the tank is full in 2 hours, from the start
Two pipes 1 and 2 can fill a tank in 2.5 hours and 4 hours respectively. If both pipes are opened together, then after what time should 1 be closed so that the tank is full in 2 hours, from the start
1). 1 hr. 10 min
2). 1 hr. 15 min
3). 1 hr. 20 min
4). 1 hr. 30 min
2 answers
Given that, two pipes P and Q can fill a tank in 2.5 hours and 4 hours resp.
∴ Efficiency of pipe 1 = 1/2.5 = 2/5 and that of pipe 2 = 1/4
Let x be the time after which pipe 1 should be closed.
According to the question, total work done by both the pipes
⇒ (1/4 × 2) + (2/5 × x) = 1
⇒ 2x/5 = 1/2
⇒ x = 1.25 hours
⇒ Time required = 1 hr 15 minGiven that, two pipes P and Q can fill a tank in 2.5 hours and 4 hours resp.
∴ Efficiency of pipe 1 = 1/2.5 = 2/5 and that of pipe 2 = 1/4
Let x be the time after which pipe 1 should be closed.
According to the question, total work done by both the pipes
⇒ (1/4 × 2) + (2/5 × x) = 1
⇒ 2x/5 = 1/2
⇒ x = 1.25 hours
⇒ Time required = 1 hr 15 min