Question

The third term of a G.P. is the square of first term. If the second term is 8, then the term is.

• A. 120
• B. 124
• C. 128
• D. 132

Answer 1

Answer: (C)

128

Answer 2

$\Rightarrow$ $a = r ^ { 2 }$. Also $a r = 8$ $\Rightarrow$ $r = 2$ and$a = 4$.

$\therefore$ $T _ { 6 } = a r ^ { 5 } = 4 \times 2 ^ { 5 } = 128$.