A is twice as good a workman as B and is, therefore, able to fini
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A is twice as good a workman as B and is, therefore, able to finish a piece of work in 30 days less than B. In how many days can they finish the work together?
A. 10
B. 15
C. 20
D. 30
Please scroll down to see the correct answer and solution guide.
Right Answer is: C
SOLUTION
Let B can do the work in x days.
A can do the work in (x - 30) days.
A is twice efficient as compared to B.
(x - 30) = x/2
x = 60 days
B can do the work in 60 days while A can do the work in 30 days.
Total time taken by A and B together to complete the work = 1/(1/60 + 1/30) = 20 days