10 boys can complete a work in 7 days and 10 girls take 14 days to complete the work. How many days will 5 boys and 10 girls take to complete the work ?
Correct Answer: 7 days
Explanation:
1 boy's 1 day work = 1/70
1 girl's 1 day work = 1/140
(5 boys + 10 girls)'s 1 day work = (5/70 + 10/140) = (1/14 + 1/14) = 1/7
5 boys and 10 girls will complete the work in 7 days.
