Question

A can complete a piece of work in 20 days and B can complete 20% of the work in 6 days. if they work together, in how many days can they finish 50% of the work.
A.6
B.8​

Answer 1

Answer: A = 20 days , 20% of B = 6 days , 1/2(A+B) = ?

20% of B = 6

(20/100) * B = 6

B = 6 * 5

B = 30 days.

Work done by A & B together

(1/A) + (1/B) = (1/20 )+ (1/30)

(1/A) + (1/B) = 50/600

(1/A) + (1/B) = 1/12 .

Now 50 % of {(1/A) + (1/B)} = (50/100) * 12

50 % of {(1/A) + (1/B)} = 6 days.

So A & B will take 6 days to complete the 50 % work.