RRB Junior Engineer Stage 1 Model Papers 3

Question : 3 of 100

Marks: +1, -0

A, B and C can do a piece of work in 10, 12 and 15 days respectively. A leaves 5 days before the completion of the work and B leaves 2 days after A. The whole work lasts for

7 days
6 days
12 days
13 days

Validate

Solution:

Suppose, the work was finished in x days. Then A‘s (x – 5) day‘s work + B‘s (x – 3) day‘s work+ C‘s x day‘s work = 1.

⇒{x-5}/10+{x-3}/12+x/15=1⇒6(x-5)+5(x-3)+4x=60

⇒6x-30+5x-15+4x=60

⇒15x=60+30+15

⇒15x=105⇒x=7 \days.

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