The task is to generate the correct answer for a given math problem.
--------
Question: Problem: a cycle is bought for rs . 900 and sold for rs . 1170 , find the gain percent ?

Answer: 30 %


Question: Problem: a sum of money at simple interest amounts to rs . 815 in 3 years and to rs . 878 in 4 years . the sum is :

Answer: 626


Question: Problem: how many digits are in ( 8 × 10 ^ 12 ) ( 10 × 10 ^ 9 ) ?

Answer:
23