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

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

Problem: if a ã — b = 2 a - 3 b + ab , then 3 ã — 2 + 2 ã — 3 is equal to :
7

Problem: a contractor undertakes to built a walls in 50 days . he employs 40 peoples for the same . however after 25 days he finds that only 40 % of the work is complete . how many more man need to be employed to complete the work in time ?

60