In a geometric progression, the first term is a and the common ratio is r. The sum of the first two terms is 12 and the third term is 16.

determine the ratio ar^2/a+ar

1 answer

In G.P:

an = a ∙ r ⁿ ⁻ ¹

a1 = a

a2 = a r¹ = a r

a3 = a r²

The sum of the first two terms is 12 means:

a1 + a2 = 12

a + a r = 12

The third term is 16 means:

a3 = a ∙ r² = 16

a r² / ( a + a r ) = 16 / 12 = 4 ∙ 4 / 4 ∙ 3 = 4 / 3