Question

While working alone at their constant rates computer X can process 240 files in 4 hours, and comp Y 240 files in 8 hrs. If all files processed by these comp. are the same size how long would it take the two comp. working at the same time at their respective constant rates , to process a total of 240 files?
A. 2hrs
B. 2hrs 20 min
C. 2hrs 40 min
D. 6hrs
E. 6hrs 20 min

Answer 1

Answer: c) 2hrs 40 min

Explanation:

Rate of working of Computer X is = 240 files/ (4 × 60min)

= 1 file / min

Rate of working of Computer Y is = 240files/ (8×60min)

= 0.5 file/min

The combined rate for computer X & Y is = 1 + 0.5 = 1.5 file/ mins.

Therefore, time taken to process 240 files is = 240/1.5

= 160mins

= 2hrs 40mins

Answer 2

Answer:

2hrs 40 min

Explanation: