Question

Ana's statistics skills have been improving during her senior year at Fletcher High School. On her first end-of-the-week assessment she scored 57 points, then she scored 61 and 65 on her next two assessments. If her scores continued to increase at the same rate, what will be her score on the 9th assessment?

Answer 1

A 1 = 57,  a 2 = 61,  a 3 = 65 ( arithmetic sequence )
a n = a 1 + ( n - 1 ) d
a 2 = a 1 + d
61 = 57 + d
d = 61 - 57 
d = 4
a 9 = 57 + 8 * 4 = 57 + 36 = 93
Answer: Her score on the 9th assessment will be 93 points. 

Answer 2

Answer:

Answer is 89

Step-by-step explanation:

Given that Ana's statistics skills have been improving during her senior year at Fletcher High School. On her first end-of-the-week assessment she scored 57 points, then she scored 61 and 65 on her next two assessments.

If her scores continued to increase at the same rate, then we can find the pattern

57,61,65

This is an arithmetic sequence with common difference =4

First term = 57

Hence 9th term would be

$a_9 =a+(9-1)d\\=57+8(4)\\=89$