CAT 2022 Slot 2 Paper

$\mathit{a}+2\mathit{b}=6$
From the above equation, we can say that maximum value $\mathit{b}$ can take is 3 and minimum value $\mathit{b}$ can take is 0 .
$\mathit{a}+\mathit{b}+\mathit{b}=6$
$\mathit{a}+\mathit{b}=6-\mathit{b}$
$\mathit{a}+\mathit{b}$ is maximum when $\mathit{b}$ is minimum, i.e. $\mathit{b}=0$
Maximum value of $\mathit{a}+\mathit{b}=6-0=6$
$\mathit{a}+\mathit{b}$ is minimum when $\mathit{b}$ is maximum, i.e. $\mathit{b}=3$
Minimum value of $\mathit{a}+\mathit{b}=6-3=3$
Average $=\frac{6+3}{2}=4.5$
The answer is option $\mathit{D}$.