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

[Q]: Problem: how much interest will $ 10,000 earn in 9 months at an annual rate of 4 % ?
[A]: $ 300

[Q]: Problem: a worker is paid a regular rate of rs . 10 for completing a survey . the worker completes 50 surveys per week . for any survey involving the use of her cellphone , she is paid at a rate of that is 30 % higher than her regular rate . if she completed 35 surveys involving the use of her cellphone , how much did she get that week ?
[A]: 605

[Q]: Problem: how many different positive integers exist between 10 ^ 3 and 10 ^ 4 , the sum of whose digits is equal to 2 ?
[A]:
4