A can complete 3/8 of a certain work in 9 days and B can complete 80% of the same work in 16 days. Both works together for 5 days. C alone completes the remaining work in 6(1/2) days. A and C together will complete the whole work in:
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 8 days.
Concept used:
Total work = Efficiency × days
Calculations:
A can complete 3/8 of a certain work in 9 days
Total days taken by A = 9 × 8/3 = 24 days
B can complete 80% of the same work in 16 days
Total days taken by B = 20 days
Total work (LCM of 24 and 20) = 120 units
Efficiency of A = 120/24 = 5 units
Efficiency of B = 120/20 = 6 units
Both works for 5 days, total work in 5 days = (5 + 6) × 5 = 55 units
Remaining work = 120 - 55 = 65 units
Efficiency of C = 65/6.5 = 10 units
Time required to complete the whole work by A and C = 120/15 = 8 days