Question

The first two terms of an arithmetic sequence are a1 = 2 and a2 = 4. What is a10,the tenth term?A. 19 B. 10 C. 18 D. 20

Answer 1

Since the difference between a1-a2 is 2, just multiply it 2x10 which is D

Answer 2

Finde the difference between each one:

d = A2 - a1 = 4-2 = 2

sequence formula:

an = a1 + (n-1) *d

a10 = 2 + (10-1) * 2

a10 = 2+9 *2

a10 = 2+18

a10 = 20

The answer is D.