It takes one machine 5 hours to complete a production order and another machine 3 hours to complete the same order. How many hours would it take both amhcines working simultaneously at their respective rates to complete the order?
Pick:
A) a) 7/12  B) b) 1 1/2  C) c) 2 2/9  D) d) 3 1/2  E) e) 7
RT = W   Given:   R = 1/5 + 1/4 = 9/20   T = ?   W = 1   T = 1 / (9/20) = 20/9 = 2 2/9   Answer: c) 2 2/9
<result>C</result>
It takes one machine 5 hours to complete a production order and another machine 3 hours to complete the same order. How many hours would it take both amhcines working simultaneously at their respective rates to complete the order?