GeminiHeat wrote:
Machine A currently takes x hours to complete a certain job. Machine B currently takes y hours to complete the same job. If x=4y, by what percent will x have to decrease so that A and B together can complete the job in 3y/8 hours ?
A. 15%
B. 25%
C. 30%
D. 62,5%
E. 85%
Let
y=1Then
x=4Now
A and
B together require
3y8 hours to finish the job, Let us assume that
A now requires
z hours for the same.
i.e.
zy(z+y)=3y8z(z+1)=388z=3z+3z=35 hours
% Change =
(4−0.60)4(100)=85%
Hence, option E