Question

Find the 31st term of the following sequence.. . 9, 15, 21, .... . . 186. 189. 195. . . is there an easy way to do this.

Answer 1

This problem is an example of an arithmetic series.

The common difference of the second term (15) with the first term (9) and the third term (21) with the second term (15) [15-9=6; 21-15=6] is 6.

The formula for solving this is:
An= A1 +(n-1)*d where An is the nth term, A1 is the first term, n is the number of terms and d is the common difference.

An=9+ (31-1)*6 = 189

The answer is 189.

Answer 2

Answer:

189

Step-by-step explanation:

1. Formula

A(n) = a + (n - 1)d

term number: n

first term: a

common difference: d

2. Solve

A(n) = 9 + (31 - 1)6

31 - 1 = 30

A(n) = 9 + 30 x 6

30 x 6 = 180

A(n) 9 + 180 = 189