Machine A produces 100 parts twice as fast as Machine B does. Machine B produces 100 parts in 80 minutes. If each machine produces parts at a constant rate, how many parts does Machine A produce in 20 minutes? Pick:  A) 60  B) 80  C) 70  D) 40  E) 50

Rationale: machine b produces 100 part in 80 minutes . machine a produces 100 parts twice as fast as b , so machine a produces 100 parts in 80 / 2 = 40 minutes . now , machine a produces 100 parts in 40 minutes which is 100 / 40 = 10 / 4 parts / minute . 10 / 4 parts x a total of 20 minutes = 10 / 4 * 20 = 50 e
Answer: E