Bunuel wrote:
Machine A, operating alone at its constant rate, produces 500 feet of a particular fiber in 2 hours. Machine B, operating alone at its constant rate, produces 500 feet of the same fiber in 3 hours. Machine C, operating alone at its constant rate, produces 500 feet of the same fiber in 5 hours. How many hours will it takes Machine A, B, and C, operating together at their respective constant rates, to produce 1,000 feet of fiber?
A. 60/31
B. 15/7
C. 25/11
D. 10/3
E. 20/3
Effciencies are
A = 500/2
B = 500/3
C = 500/5
Combined efficiency of A + B + C = 1550/3
So, Time required to produce 1000 feet is : 1000*3/1550 = 300/155 = 60/31, Answer is clearly (A)
Statistics : Posted by Abhishek009 • on 15 Sep 2020, 05:30 • Replies 4 • Views 2931