RRB Junior Engineer Stage 1 Model Papers 6

Question : 25 of 99

Marks: +1, -0

Three pipes A, B and C can fill a tank in 6 hours. After working it together for 2 hours, C is closed and A and B can fill the remaining part in 7 hours. The number of hours taken by C alone to fill the tank is

Validate

Solution:

1/A+1/B+1/C=1/6

(A + B + C)

can do

2/6=1/3(A + B + C)

part of work in 2 days.
Remaining work

=1-1/3=2/3

In one hour

(A + B)

can do

2/{3×7}

part of work

1/C=1/6-(1/B+1/C)

1/C=1/6-2/21=3/42

C=14 hours

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