The task is to generate the correct answer for a given math problem.
--------
Question: Problem: a certain elevator has a safe weight limit of 2,000 pounds . what is the greatest possible number of people who can safely ride on the elevator at one time with the average ( arithmetic mean ) weight of half the riders being 200 pounds and the average weight of the others being 230 pounds ?

Answer: 9


Question: Problem: if the sides of a triangle are 26 cm , 24 cm and 15 cm , what is its area ?

Answer: 180


Question: Problem: the cost price of an book is 64 % of the marked price . calculate the gain percent after allowing a discount of 12 % ?

Answer:
37.5 %