Question

Find the value of $a$.

• A. $12$
• B. $18$
• C. $24$
• D. $32$

Answer 1

Answer: (B)

$18$

$xy=2\times 36=3\times 24=72=k_1\Rightarrow x\propto \frac{1}{y}$
$xz=3\times 16=6\times 8=48=k_2\Rightarrow x\propto \frac{1}{z}$
$xy=k_1,xz=k_2$
$\Rightarrow \frac{xy}{x_2}=\frac{k_1}{k_2}$
$\Rightarrow \frac{y}{2}=\frac{k_1}{k_2}=k_3$
$\Rightarrow y\propto z$
$2\times 36=a\times 4=b\times 9=3\times 24=8\times c=6\times d=72$
$\Rightarrow a=\frac{72}{4}=18$