Algebra 2 Question

Question

A group of students take a test and the average score is 65. One more student takes the test and receives a score of 90 increasing the average score of the group to 70. How many students were in the initial group?

Answer 1

(65x + 90) \ (x + 1) = 70

The unknown must be multiplied by 65 representing the number of kids who averaged 65. Add 90 and divide by x + 1 representing the new total number of kids.

Multiplying both sides by x+1, we get

65x + 90 = 70(x + 1)

65x + 90 = 70x + 70

5x = 20

x = 4

There were originally 4 students