Anu is four times as good as Binni in completing a task. Together they finish the same task in 7 hours. In how many hours will Anu alone complete the task?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 35/4
Let Binni do x units an hour, then Anu does 4x units an hour.
Given, x + 4x = 1/7
⇒ 5x = 1/7 ⇒ x = 1/35
If Anu does 4x units an hour, then she will complete 4/35 units of work in an hour.
Thus, she will complete the whole work in 35/4 hours.