A, B and C can do a piece of work in 20, 40 and 80 days respectively. In how many days can A do the work if he is assisted by B and C on every third day?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 161/4 days
Let total work be LCM of 20, 40, 80 = 80 units.
Efficiency = total work / number of days.
Efficiency of A = 80/20 = 4 Units.
Efficiency of B = 80/40 = 2 Units.
Efficiency of C = 80/80 = 1 Unit.
A do the work if he is assisted by B and C on every third day then,
work done in 3 days will be = 4 + 4 + 4 + 2 + 1 = 15
in 15 days work done will be 15 × 5 = 75 unit
on 16th day 4 unit work will be done by A
Now 1 unit work is remaining and will be done by A in 1/4 days
so total days are 161/4 days