Question

A and B can do a piece of work in 18 and 12 days they begin together but we leave 3 days before the completion of the work in how many days the work in finished

Answer 1

a and b can do piece of work in18 and 12 then it leaves together for 3 days then
a work= 18-3=15, b work=12-3=9
a and b work= 15+9=24days

Answer 2

a=18
b=12
lcm=36
efficiency a:2 b:3
b 3 day work=3×3=9
36+9=45
45/5=9
work finished in 9 days