Question

Consider the sequence $8 A +2 B , 6 A + B , 4 A , 2 A - B , \ldots \ldots . .$. Which term of this sequence will have a coefficient of A which is twice the coefficient of B?

• A. $10^{\text {th }}$
• B. $14^{\text {th }}$
• C. $17^{\text {th }}$
• D. none

Answer 1

Answer: (D)

Coefficient of A in $n^{\text {th }} \text { term }=8+(n-1)(-2) $
$=10-2 n $
$\text { coefficient of } B \text { in } n^{\text {th }} \text { term }=2+(n-1)(-1) $
$=3-n$
$10-2 n=2(3-n) \Rightarrow 10=6 $
$\text { which is absurd } \Rightarrow \text { none }$