Given:
The sum of two terms of GP is 6 and that of first four terms is 
To find:
The sum of first six terms.
Solution:
We have,


Sum of first n terms of a GP is
...(i)
Putting n=2, we get


...(ii)
Putting n=4, we get



(Using (ii))
Divide both sides by 6.
Taking square root on both sides, we get

Case 1: If r is positive, then using (ii) we get
The sum of first 6 terms is




Case 2: If r is negative, then using (ii) we get
The sum of first 6 terms is




Therefore, the sum of the first six terms is 7.875.
Answer:
28 
Step-by-step explanation:
21/2 * 8/3 = 28
1. In a week there are 7 days. So your andwer would be 21/10. The decimal is 2.1.
1) 108
2) 72
3) 36
4) 72
5) 72
6) 144
7) 72
8) 72
9) 108
10) 108
I hope this helped
Answer:
387420489
Step-by-step explanation:
9 x 9 x 9 x 9 x 9 x 9 x 9 x 9 x 9 = 387420489
Have a lovely day! ~Pooch ♥