Question : A and B together can complete a project in 10 days. They started together, but A left after 2 days and the remaining work was completed by B in 12 days. In how many days can A complete the entire work while working alone?
Option 1: 15 days
Option 2: 20 days
Option 3: 30 days
Option 4: 45 days
Correct Answer: 30 days
Solution :
Given: A and B together can complete a project in 10 days.
Let the efficiency of A is
Total work = Efficiency × Time
Total work is
They started together, but A left after 2 days and the remaining work was completed by B in 12 days.
⇒
⇒
⇒
Then, the efficiency of A is 1 unit and the efficiency of B is 2 units.
Total work is
Time taken by A to complete the whole work is
Hence, the correct answer is 30 days.
