Question

The first term of an arithmetic sequence is -3 and the 15th term is 53. What is the common difference of the sequence?

Answer 1

c = 4

Explanation:

Let the common difference be c. Then a(n) = -3 + c(n-1). Since a(15) = 53, a(15) = -3 + (15-1)c = 53. Therefore, -3 + 14c = 53, or 14c = 56; c = 4.