If 50 is the first number, what is the second number?

Answer 1

Your subject area is MATH, not the name of your school.

There is not enough information here to know what the next number is. Isn't there more to this question?

Answer 2

If 50 is the first number, and we count by 50's, the next number is 100.

We need to know the step between the numbers. As Writeacher said, the question seems incomplete.