Question

Two typists A and B are working on an assignment. A takes 6 hrs to type 32 pages and B takes 5 hrs to type 40 pages. How much time will they take, working together on two computers to type an assignment of 100 pages?
1. 8 hrs 25 min
2. 8 hrs
3. 8 hrs 15 min
4. 7 hrs 30 min

Answer 1

Correct Answer - Option 4 : 7 hrs 30 min

Given:

A takes 6 hrs to type 32 pages.

B takes 5 hrs to type 40 pages.

Concept Used:

Work done  = 1/Time 

Calculation:

A takes 6 hrs to type 32 pages.

A's 1 hour work = 32/6

B takes 5 hrs to type 40 pages.

B's 1 hour work = 40/5 = 8

(A + B)'s 1 hour work = 32/6 + 8 = 80/6

Time taken to type 100 pages by (A + B) together = (100/80) × 6 = 15/2 = 7 hours 30 min

∴ Time taken to type 100 pages by (A + B) together is 7 hours 30 min