Question

Write an expression to describe the sequence below, and then find the 7th term. Use n to represent the position of a term in the sequence, where n = 1 for the first term.

7, 14, 21, 28, ...


an =


a7 =

Answer 1

The given sequence is arithmetic

Given,

first term (a) = 7

Common difference (d) = 7

number of terms (n) = 7

we know,

Tn = a + (n-1) × d

T7 = 7 + (7-1) × 7

T7 = 7 + 6 × 7

T7 = 7 + 42

Therefore T7 = 40