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

[Q]: Problem: in how many no . between 10 and 30 exactly two of the digits is 2 ?
[A]: 1

[Q]: Problem: how many liters of a 40 % iodine solution need to be mixed with 35 liters of a 20 % iodine solution to create a 34 % iodine solution ?
[A]: 13

[Q]: Problem: if the cost price of 24 chocolates is equal to the selling price of 16 chocolates , the gain percent is :
[A]:
50 %