9514 1404 393
Answer:
d. 40 days
Step-by-step explanation:
If 20 men are equivalent to 30 boys, then half as many, 10 men, are equivalent to 15 boys.
The work output of 10 man and 12 boys is then equivalent to the work output of 15 +12 = 27 boys.
The time required is inversely proportional to the workforce, so 27 boys, instead of 30, will take 30/27 = 10/9 times as long as 36 days to do the work
(10/9)×(36 days) = 40 days
10 men and 12 boys can do the work in 40 days.
