Question

$x:2a46b$

$y:1025c3045$

$z:90def20$ $x,y,z$ are proportional to each other. Find the value of $b+c$

• A. $36$
• B. $29$
• C. $30$
• D. $32$

Answer 1

The correct option is B $29$

$\frac{x}{y}=\frac{2}{10}=\frac{6}{30}=\frac{1}{5}=constant\Rightarrow x\propto y$

$y\times z=10\times 90=45\times 20=900=constant\Rightarrow y\propto \frac{1}{z}$

$x\propto y$ and $y\propto \frac{1}{z}\Rightarrow x\propto \frac{1}{z}$

$\frac{2}{10}=\frac{a}{25}=\frac{4}{c}=\frac{6}{30}=\frac{b}{45}=\frac{1}{5}$

$\Rightarrow c=4\times 5=20,b=\frac{45}{5}=9$
$\Rightarrow b+c=9+20=29$