A, B and C can do a piece of work in 24 days, 30 days and 40 days respectively. They began the work together but C left 4 days before the completion of the work. In how many days was the work completed?
Answers
A can do a piece of work in 24 days
One day's work of A=1/24 part
B can do a piece of work in 30 days
One day's work of A=1/30 part
C can do a piece of work in 40 days
One day's work of C=1/40 part
One day's work of A, B and C = (1/24 + 1/30 + 1/40) = 1/10.
C leaves 4 days before completion of the work, which means only A and B work during the last 4 days.
Work done by A and B together in the last 4 days = 4 (1/24 + 1/30) = 3/10.
Remaining Work = 7/10, which was done by A,B and C in the initial number of days.
Number of days required for this initial work = 7 days.
Thus, the total numbers of days required = 4 + 7 = 11 days. ANS
in 1 day A+B+C can do= {1/24+1/30+1/40}= 1/10 part of work
after 4 days C left the work
so [A + B] working only
work of [A + B] together in 4 days ={1/24+1/30}4
=3/10 part of work
work left=1- 3/10 =7/10
nos.of days needed=7 days
total numbers of days needed=4+7
=11 days.
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