# To do a certain work the ratio of efficiency of A to that of B is 3 :

| To do a certain work the ratio of efficiency of A to that of B is 3 : 7. Working together, they can complete the work in days. They work together for 8 days. 60% of the remaining work will be completed by A alone is :

A. days

B. 5 days

C. 4 days

D.

### Right Answer is: B

#### SOLUTION

Note: For this question, discrepancy is found in question/answer. Full Marks is being awarded to all candidates.

Ratio of efficiency of A : B = 3 : 7

A. T. Q.

When they work together, total work done by A and B in an hour = (3+7) unit = 10 unit

Hence,

Total work

Work done by A and B in 8 days = 10 × 8 = 80

Remaining work = 105 – 80 = 25

60% of Remaining work

Required days by A to complete the 60% of Remaining work

= 5 days

Share

To do a certain work the ratio of efficiency of A to that of B is 3 :