Question

A student has taken three math tests so far this semester. His scores for the first three tests were 71, 75, and 79. Part A: Suppose his test scores continue to improve at the same rate. What will be the grade on the sixth and (final) test?

Answer 1

The grade of this sixth and (final) test would be 91.

Explanation:

This is an arithmetic series since each time the data is increasing by the common difference of 4, and we already know a₁ which is the first term in the sequence is 71, therefore we can say:

a₁ = 71

r = 4

a₆ = the sixth term that needs to be found out

n = 6

Formula of an arithemetic series:

aₙ = a₁ + r(n - 1)

a₆ = 71 + 4(6 - 1)

a₆ = 71 + 4(5)

a₆ = 71 + 20

a₆ = 91

Hence, the grade of this sixth and (final) test would be 91.

Hope this helps!