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 score 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.