Respuesta :
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