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

[Q]: Problem: two cars start at the same time from opposite ends of a highway that is 175 miles long . one car is riding at 25 mph and the second car is riding at 45 mph . how long after they begin will they meet ?
[A]: 2.5


[Q]: Problem: if the cost price of 50 articles is equal to the selling price of 40 articles , then the gain or loss percent is ?
[A]: 25 %


[Q]: Problem: the average of 10 numbers is 0 . in those 10 , at the least , how many may be greater than or equal to zero ?
[A]:
1