Question

What is the value of the 11th term in the sequence -3, -6, -12, -24, ...?

-118,098
-3,072
-6,144
-354,294

Answer 1

Given ,

$\star \sf \: \: First \: term \: (a) = -3 \\ \\ \star \sf \: \: </p><p>Common \: ratio \: (r) = \frac{ - 6}{ - 3} = 2$

We know that , general term of the GP is given by :

$\large \sf \underline{ \: \fbox{ a_{n} = a {(r)}^{n - 1} } \: }$

Substitute the values , we obtain

$\implies \sf a_{11} = - 3 {(2)}^{11 - 1} \\ \\ \implies \sf a_{11} = - 3 \times 1024 \\ \\\implies \sf a_{11} = - 3072$

Hence , the 11th term of the GP is -3072