instruction:
The task is to generate the correct answer for a given math problem.
question:
Problem: 90 % of the population of a village is 36000 . the total population of the village is ?
answer:
4000


question:
Problem: a company pays 12.5 % dividend to its investors . if an investor buys rs . 60 shares and gets 25 % on investment , at what price did the investor buy the shares ?
answer:
30


question:
Problem: an empty fuel tank with a capacity of 200 gallons was filled partially with fuel a and then to capacity with fuel b . fuel a contains 12 % ethanol by volume and fuel b contains 16 % ethanol by volume . if the full fuel tank contains 28 gallons of ethanol , how many gallons of fuel a were added ?
answer:

100