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

Problem: a gambler has won 40 % of his 40 poker games for the week so far . if , all of a sudden , his luck changes and he begins winning 70 % of the time , how many more games must he play to end up winning 60 % of all his games for the week ?
80

Problem: in traveling from a dormitory to a certain city , a student went 1 / 5 of the way by foot , 2 / 3 of the way by bus , and the remaining 10 kilometers by car . what is the distance , in kilometers , from the dormitory to the city ?
62

Problem: on a certain date , pat invested $ 7,000 at x percent annual interest , compounded annually . if the total value of the investment plus interest at the end of 10 years will be $ 28,000 , in how many years total will the total value of the investment plus interest increase to $ 56,000 ?

15