Question

The first term of an arithmetic sequence is -3 and the fifteenth term is 53.

What is the common difference of the sequence?

A. 14/13
B. 25/7
C. 4

Answer 1

To find term \(a_n\), use this formula:

\(a_n = a_1 + (n - 1)d\)

You have \(a_1 = -3\), \(n = 15\), \(a_{15} = 53\)

Answer 2

Substitute those values in the formula, and solve for d.

Answer 3

x = a + d(n-1)
53 = -3 +d(15-1)
56 = 14d