Saturday, January 19, 2008

Problem Solving - 38

6 machines, each working at the same constant rate, together can complete a certain job in 12 days, How many additional machines, each working at the same constant rate, will be needed to complete the job in 8 days?
A. 2
B. 3
C. 4
D. 6
E. 8

Answer: B

6
machines take = 12 days.
Therefore 1 machine = 12*6 days.
8 days will take = (12*6)/8 = 9 machines.

No of additional machines required = 9-6 = 3