Question

Two pipes a and b fill a tank in 15 hours and 20 hours while a third pipe C can empty the full tank in 25 hours all the three pipes are opened after 10 hours C is closed in how much time will the tank be full?​

Answer 1

hi friend

here your answer

a's 1 hr work = 1/15

b's 1 hr work = 1/20

c's 1 hr work = 1/25

In 1 hr, d tank filled ll be

1/15 + 1/20 - 1/25 = 20+15-12/300 = 23/300

In 10 hrs , 10 * 23/300 = 23/30

Remaining part = 1 - 23/30 = 7/30

c is closed,,, a+b is opened...

a+b's 1 hr work = 1/15 + 1/20 = 35/300 = 7/60

a+b ll fill

1 hr -- 7/60

x ---- 7/30

x = 7/30 * 60/7 = 2hrs

The tank ll be filled in 10 + 2 = 12hrs

Ans : 12 hrs

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