Question

Which term of the gp : 5, -10, 20, -40, is 320

Answer 1

Answer:

here your answer.....

Step-by-step explanation:

here

a=5

common ratio (r) =-10/5=-2

atq

320=ar power of n-1

320=5*-2^n-1

64=-2^n-1

-2^6=-2^n-1

6=n-1

n=7

Answer 2

Answer:

320 is 7th term of given GP

Step-by-step explanation:

Given data

 5, -10, 20, -40..   is in GP

Here we need to find which term will be 320 in given GP

From given data  

First term of GP a = 5

common ratio r =  a₂/a₁ = -10/5 = -2

let 320 is nth term in GP

As we know nth term of GP = arⁿ⁻¹

Therefore, arⁿ⁻¹ = 320

                (5)(-2)ⁿ⁻¹ = 320

                    (-2)ⁿ⁻¹ = 64

                    (-2)ⁿ⁻¹ = (-2)⁶  

Therefore,   n-1 = 6

                      n = 7