Q: One copy machine can make 30 copies a minute, and a second copy machine makes 15 copies a minute. If the two copiers work together, how long would it take them to make 900 copies?
Options:
(A) 15 minutes
(B) 20 minutes
(C) 25 minutes
(D) 30 minutes
(E) 35 minutes Let's give some random thoughts before answering.
Total work done by both machines in a minute = 30 + 15 = 45 copies
Total number of copies required = 900
Time = 900/45 = 20 mins
Therefore, the answer is (B).