instruction:
Given a math problem with context and a question and 5 answer choices, the task is to provide the correct answer choice based on the problem. You must choose one of the given answer choices by letter: a, b, c, d, or e; anything else is invalid.
question:
Problem: a mixture of 70 litres of milk and water contains 10 % water. how many litres of water should be added to the mixture so that the mixture contains 12 1 / 2 % water ?
Options: a. 2, b. 8, c. 6, d. 3, e. 4
answer:
a


question:
Problem: the average age of a family of 5 members is 20 years. if the age of the youngest member be 10 years then what was the average age of the family at the time of the birth of the youngest member ?
Options: a. 13.5, b. 14, c. 15, d. 12.5, e. none
answer:
d


question:
Problem: a gambler has won 40 % of his 20 poker games for the week so far. if, all of a sudden, his luck changes and he begins winning 80 % of the time, how many more games must he play to end up winning 60 % of all his games for the week ?
Options: a. 20, b. 25, c. 30, d. 35, e. 40
answer:

a