Given: second term of a GP is 24 and its fifth term is 81.

To find: sum of first five terms of the G.P.

ar = 24 & ar⁴ = 81

dividing these two terms we get:

⇒

⇒

Taking cube root on both the sides we get,

⇒

_{Substituting this value of r in ar = 24 we get}

_{a = 24/(3/2) = (24 × 2)/3 = 16}

∴ Sum of first Five terms of a G.P. = a(rⁿ - 1)/(r - 1)

=

=

Ans:242