Question

Each number in a list of numbers can be found using the expression 6 − 2/3 (n − 1), where n is a positive integer that gives the position of the number in the list. What is the thirteenth number in the list?

A. −8
B. −2
C. 8
D. 13

Answer 1

B. −2

Explanation:

You want the value of the expression 6 -2/3(n -1) for n = 13.

Evaluation

Put 13 where n is in the expression and do the arithmetic.

= 6 -2/3(13 -1) . . . . . . substitute for n

= 6 -2/3(12) . . . . . . evaluate the parentheses

= 6 -8 . . . . . . . . . evaluate the product

= -2 . . . . . . . . evaluate the difference

The 13th number in the list is -2.