Question

Eighteen boys can do a piece of work in 20 days and
24 girls can complete the same work in 15 days.
If 16 boys alone work for the first six days and
20 girls join them for next three days, then what part
of the work remains after 9 days?​

Answer 1

( 16 boys+ 12 girl ) 30 D = 18 girl * 60 D

480 boys + 360 girls = 1080 girl

480 boys = 720 girls

2 boys = 3 girls

18 boys = 27 girls

24 boys * 30 D = 30 boys * x

x = 24 days