The task is to generate the correct answer for a given math problem.
--------
Question: Problem: convert 2 / 5 to a decimal

Answer: 0.4


Question: Problem: a cistern is normally filled in 6 hours but takes two hours longer to fill because of a leak in its bottom . if the cistern is full , the leak will empty it in ?

Answer: 24


Question: Problem: a building contractor employs 20 male , 15 female and 5 child workers . to a male worker he pays rs . 25 per day , to a female worker rs . 20 per day and a child worker rs . 8 per day . the average wage per day paid by the contractor is ?

Answer:
21