Question

Find the 29th term of the following sequence.

13.1 3.1 -6.9 -16.9, . . .

A. -286.9

B. -266.9

C. -296.9

D. -276.9

Answer 1

Arithmetic sequence
a₁ = 13.1; a₂ = 3.1; a₃ = -6.9; a₄ = -16.9... a₂₉ = ?

the common difference:
d = a₂ - a₁ = 3.1 - 13.1 = -10

29th term:
a₂₉ = a₁ + d(n-1)
= 13.1 + (-10)(29-1)
= 13.1 -10*28
= 13.1 - 280
= -266.9