A can finish a work in 24 days and B in 30 days, individually. They work together for 11 days. The percentage of the work still to be finished will be:
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 17.5%.
Total work = 120 (LCM of 24 and 30)
Efficiency of A and B = (120/24) + (120/30) = 5 + 4 = 9 units/day
Work done by A and B in 11 days = 11 × 9 = 99 units
Remaining work = 120 - 99 = 21 units
Required percentage = (21/120) × 100 = 17.5%
Therefore, 17.5% of the work still needs to be finished.