First, we need to determine if the sequence is an arithmetic or a geometric. So the arithmetic sequence is referred to a sequence that the difference between the numbers is constant. While the geometric sequence is a sequence where each number after the first is identified by multiplying the previous one by a fixed number.
Given
57, 61, 65 the difference between the numbers is 4
Solution
Arithmetic sequence
An= 65+4 An= 69+4 An= 73+4 An= 77+4 An= 81+4 An= 85+4
An= 69 An= 73 An= 77 An= 81 An= 85 An= 89
The score of Edgar for his 9th quiz is 89 points.
