A G.P has its 3rd term and 7th term as 45 and 3645 respectively. what is the product of its 2nd and 4th
+2234
A G.P has its 3rd term and 7th term as 45 and 3645 respectively. what is the product of its 2nd and 4th
Call the common ratio "r"
1st term
2nd term 45 / r
3rd term 45 45
4th term 45 • r
5th term 45 • r • r
6th term 45 • r • r • r
7th term 45 • r • r • r • r 3645
8th term 45 • r • r • r • r • r
Taking what we know, then 45 • r4 = 3645
r4 = 3645 / 45 = 81
r1 = 3
4th term is 45 • 3 = 135
2nd term is 45 / 3 = 15 Ha ha, I bit. It wasn't even necessary to solve for r.
No matter what r is, it cancels out in the 2nd and 4th.
product of 2nd times 4th = 2025
.
