Question

If the 5th term in a geometric sequence is 162, and the common ratio is 3. What is the first term in the sequence?

Answer 1

2

Explanation:

a2 = a1×3

a3 = a2×3 = a1×3×3

=>

an = an-1 × 3 =

`a1 * {3}^(n - 1)`

a5 = 162 = a1×3⁴ = a1×81

a1 = 162/81 = 2