The task is to generate the correct answer for a given math problem.

Problem: a work as fast as b . if b can complete a work in 8 days independently , the number of days in which a and b can together finish the work in ?
2 2 / 3 days

Problem: the cost of the paint is rs . 50 per kg . if 1 kg of paint covers 20 sq . ft , how much will it cost to paint outside of a cube having 20 feet each side
rs . 6000

Problem: what is the smallest integer that is multiple of 5 , 7,9

b ) 315