Mathematics

The common ratio of a G.P. is 2. If the 5th term is greater than…

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,
  • A.
    3
  • B.
    6
  • C.
    45
  • D.
    48
  • E.
    90
Correct Answer: Option D
Explanation

a = 1st term ; ar4 = 5th term
∴ ar4 = a(2)4 = 16a; 16a = 45 + a, a = 3;
3(2)4 = 48