Question

The 6 term of a G.P is -2\27 and it's first term is 18.what is the common ratio​

Answer 1

Answer:

r = - $\frac{1}{3}$

Step-by-step explanation:

The n th term of a GP is

$a_{n}$ = a₁ $r^{n-1}$

where a₁ is the first term and r the common ratio

Here a₁ = 18 and a₆ = - $\frac{2}{27}$ , then

18 $r^{5}$ = - $\frac{2}{27}$ ( divide both sides by 18 )

$r^{5}$ = - $\frac{1}{243}$ ( take the fifth root of both sides )

r = $\sqrt[5]{-\frac{1}{243} }$ = - $\frac{1}{3}$