A can copy 50 papers in 10 hrs., while A & B can copy 70 papers in 10 hrs. How many hours are required for B to copy 26 papers?
10 hours
15 hours
12 hours
13 hours
Explanation:
A can copy 50 papers in 10 hrs., while A & B can copy 70 papers in 10 hrs.
It means B can copy 20 papers in 10 hrs.
Then time taken by B to copy 26 papers = 26 $\times$ 10/20 = 13 hours.