Question

Find the 15th term of the sequence 45, 48, 51, 54

Answer 1

87

Explanation:

nth term = a + d(n - 1)

d = 48 - 45 = 3

a = 45

15th term = 45 + 3(15 - 1) = 87

Answer 2

a₁₅ = 87

Explanation:

there is a common difference between consecutive terms in the sequence , that is

48 - 45 = 51 - 48 = 54 - 51 = 3

this indicates the sequence is arithmetic with nth term

`a_(n)` = a₁ + (n - 1)d

where a₁ is the first term and d the common difference

here a₁ = 45 and d = 3 , then

a₁₅ = 45 + (14 × 3) = 45 + 42 = 87