Question

20, 10, 5,?, 40, 5,? 8, 5.

Answer 1

Answer:

Explanation:-

5, 10, 20, 40, ……………………

Then, 5 x 2 = 10,    10 x 2 = 20,      20 x 2 = 40 …………….

Then, a = 5  and r = 2

Therefore, the given series is G. P. (Geometric Progression),

Let the number of terms be n.

Then, 5 x 2n – 1 = 1280

2n – 1 = 1280/5

2n – 1 = 256

2n – 1 = 28

n – 1 = 8

n  = 8 + 1

n = 9

Then, the 9th term is 1280.