A can do a piece of work in 12 days. A and B together do the work in 8 days. How long would B alone take to complete the work?
- 8 days
- 10 days
- 15 days
- 18 days
- 24 days
The Usual Method
A in one day will finish th of the work.
Let B finish th of the work in one day.
Estimated Time to arrive at the answer = 45 seconds.
Should B take 12 days working alone, than A and B working together would take 6 days. But A and B together actually take 8 days; hence B would take more than 12 days to finish the work working alone. This eliminates options ‘1’ and ‘2’
Also note that the difference between 6 days and actual 8 days is that of 2 days. Simply multiplying 2 with 12 we get 24 days which is the answer.
Estimated Time to arrive at the answer = 10 seconds.