Question

The 3rd and 6th terms of a G.P. are 40 and 320, then find the progression.

Answer 1

T₃ ⇒ ar² = 40

T₆ ⇒ ar⁵ = 320

`(ar^5)/(ar^2) = 320/40`

r³ = 8

r = 2

a(4) = 40

a = `40/4`

a = 10

GP ⇒ a, ar, ar2 ...

10, 20, 40, ....