Question

The first term of an arithmetic sequence is 4 and the tenth term is 67.

What is the common difference? Show your work or explain your answer.

Answer 1

Explanation:

Formula

tn = a1 + (n-1)* d

Givens

tn = 67 (it is the last term or the nth term

n = 10

a1 = 4

find d

Solution

67 = 4 + (10 - 1)*d

67 = 4 + 9*d Subtract 4 from both sides

67 - 4 = 9d

63 = 9d Divide by 9

63/9 = 9d/9

7 = d

Remark: This is a fundamental application of the arithmetic sequence. You pretty much have to know how to juggle it's parts.