The common ratio of a G.P is 2. If the 5th term is greater than the 1st term by 45, find the 5th term

Answer 1

If the first term of a GP is ‘a’ and the common ratio is r, then the n’th term is: ar^(n − 1).

5th term is greater than 1st term by 45. ar^4 - a = 45.

Substitute r = 2 in the expression.

a*2^4 - a = 45

16a - a = 45

15 a = 45

a = 3

5th term = ar^(5 -1) = 3 * 2^4 = 48