Answer 1

Given G.P. : 1 + 4 + 16 + 64 +...........
Here,
first term, a = 1
common ratio, r = `4/1=4` (r > 1)
Let the number of terms to be added = n
Then, S_n = 5461

`=>(a(r^n-1))/(r-1)=5461`

`=> (1(4^"th"-1))/(4-1)=5461`

`=>(4^"th"-1)/3=5461`

⇒ 4^th - 1 = 16383

⇒ 4^th = 16384

⇒ n = 7

Hence, required number of terms = 7