A and Bcan doa job in 10 days and 5 days, respectively. They worked together for two days, after which B was replaced by C and the work was finished in the next three days. How long will C alone take to finish 40% of the job?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is Option 4 i.e 12 days.
Efficiency = Total work/Time taken
Calculation:
LCM of 10 and 5 = 10 = Total work
Efficiency of A = 10/10 = 1 unit/day
Efficiency of B = 10/5 = 2 units/day
A and B work for 2 days
⇒ (1 + 2) × 2 units = 6 units
Remaining work = (10 - 6) units = 4 units
A and C can complete the remaining work in 3 days
⇒ A and C one day work = 4/3
⇒ C one day work = (4/3) - 1 = 1/3
⇒ C can complete 40% of work in = 4/1/3 = 4 × 3 = 12 days
Thus, C can complete 40% of the work in 12 days