Question

What is the common difference in the following arithmetic sequence?

2/3, 1,6, -1/3, -5/6........

A.) -4
B.) -1/2
C.) 1/9
D.) 4

Answer 1

Answer:

B. -1/2

Explanation:

The common difference is the difference between the numbers in your arithmetic sequence. In this case, we see that the numbers are getting smaller, so we can start by setting up this equation:

2/3 - 1/6

Because these fractions don't have a common denominator, you make them equal by changing the fractions to have a common denominator. The LCM is 6, so we multiply the first fraction by 2/2:

4/6 - 1/6 = 3/6


3/6 can be simplified to be 1/2, and we know we're subtracting, so the answer is b.