Question

The sequence below shows the number of households that have purchased a subscription to a magazine each month 3,9,27,81, 243. What formula to determine the number of households

Answer 1

a(n) = 3*3^(n-1).

Explanation:

The first term of this sequence is 3. The next one is 3 times 3, or 9; the next is 3 times 9, or 27; and so on. So the common ratio is 3.

The formula for the nth term is thus a(n) = 3*3^(n-1).