Correct Answer - Option 1 : 45 days
Given:
A and B together finish work = 30 days
B left the work = 20 days after working together
Remaining work finished by A = 15 days
Formula used:
Efficiency = Total work/Time
Calculation:
Let the total work done by A and B be 30 units
According to the question
Total work done by A and B in 20 days = 20 units
Remaining work = (30 - 20) units = 10 units
Since, B left after 20 days and remaining work completed by A alone in 15 days
Efficiency of A = 10/15 = (2/3) units per day
Time taken by A to finish job alone = [30/(2/3)]
⇒ (30 × 3)/2
⇒ 45 days
∴ A can alone finish the job in 45 days.
