Arithmetic Sequence Terms

Question

Suppose an arithmetic sequence is defined by this explicit formula.

an = 20 + (n − 1)4
Question 1
Determine a25.
Responses

A45
45
B116
116
C130
130
D162

Answer 1

To determine a25, we substitute n = 25 into the formula.

a25 = 20 + (25 - 1)4

a25 = 20 + 24*4

a25 = 20 + 96

a25 = 116

Therefore, the correct answer is B) 116.