A, B and C can do a piece of work in 10, 20 and 30 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: C
Explanation
The correct answer is option 3 i.e. 8 days
Let the total work be the LCM of 10,20 and 30
Total work = 60 unit
We know, Efficiency = Total work/Number of days taken
Efficiency of A = 60/10 = 6
Efficiency of B = 60/20 = 3
Efficiency of C = 60/30 = 2
If A is assisted by B and C on every third day then,
Total work in 3 days = 6 + 6 + (6 + 2 + 3) = 23
Total work in 6 days = 23 + 23 = 46
In 8 days total work done = 46 + 6 + 6 = 58
On 9th day all three will work hence required days = 2/11 days
Total days = 8 + 2/11 = 8 days