A, B and C can complete a piece of work separately in 10, 20 and 40 days, respectively. In how many days will the work be completed if A is assisted by both B and C every third day?
Answer & explanation
Correct answer: option 1
A = 10D, B = 20D, C = 40D,
Since A is working daily and B & C assist him on every third day, the efficiencies will be as follows:
1st day (A) = 4 units
2nd day (A) = 4 units
3rd day (All) = 4 + 2 + 1 = 7
Every 3 days work = 4 + 4 + 7 = 15
Hence, in 6 days, 30 units of work will be completed
and in 8 days. 38 units of work will be completed.
The remaining work i.e; 2 units will be completed by all of them in = \(\frac{2}{7}\) days.
Therefore, The Total time taken to complete work will be = 8 + \(\frac{2}{7}\)
= \( { 8}_{ 7}^{ 2} \)days.