Question

Find the 7th term of the arithmetic sequence 3, 15, 75, ...

Answer 1

a₇ = 46 875

Explanation:

15:3 = 5 and 75:15 = 5

so this is a geomertic sequence with common ratio of 5

a₁ = 3, r = 5

aₙ = a₁ rⁿ⁻¹

a₇ = 3(5)⁶ = 3(15 625) = 46 875