24 boys can complete a work in 12 days while 16 men can complete the same work in 9 days. In How many days will 12 boys and 12 men together complete the same work?

∵ In 12 days the work is done by = 24 boys
∴ In 1 day the work is done by = 24 x 12 = 288 boys
∵ In 9 days the work is done by = 16 men
∴ 1 day work is done by = 16 x 9 = 144 men
⇒ 144 men = 288 boys
⇒ 1 men = 288/144 = 2 boys
⇒ 12 men + 12 boys = 12 x 2 + 12 = 36 boys
∵ 24 boys complete 1 work in 12 days
∴ 36 boys complete 1 work in (12 x 24)/36 = 8 days