Central middle school has 2,470 students and the ratio of students to teacher is 26: 1. how many new teachers are needed to reduce this ratio to 19: 1?

First, it would be helpful to find out how many teachers there are at the school.

2470 students x (1 teacher/26 students)=95 teachers

To find the number of teachers needed, just use the ideal ratio:
2470 students x (1 teacher/19 students)=130 teachers

So to reduce this ratio to 19:1, the school needs 130 teachers. To know how many new teachers the school needs, just subtract the ideal from the current amount.
130-95=35 new teachers needed