Question

If $a+1,2a+1,4a-1$ are in arithmetic progression, then the value of $a$ is

• A. 1
• B. 2
• C. 3
• D. 4
• E. 5

Answer 1

Answer: (B)

We have,
$a+1,2a+1;4a-1$ are in $AP$
$\therefore 2(2a+1)=(4a-1)+(a+1)$
$[\because$ If $a,b,c$ are in $AP$, then $2b=a+c]$
$\Rightarrow 4a+2=5a$
$\Rightarrow a=2$