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

Ex Input:
Problem: the average ( arithmetic mean ) of 8 numbers is 43.1 . if the sum of half of these numbers is 158.4 , what is the average of the other half ?

Ex Output:
46.6

Ex Input:
Problem: if the personal income tax rate is lowered from 46 % to 32 % , what is the differential savings for a tax payer having an annual income before tax to the tune of $ 36000 ?

Ex Output:
$ 5040

Ex Input:
Problem: if - 3 x + 5 y = 48 and 3 x - 2 y = 6 , what is the product of x and y ?

Ex Output:
252