Question

If $x:y=1:7$ and $y:z=4:5$, find
$x:y:z$

Answer 1

Given

$\frac{x}{y}=\frac{1}{7}...........\left(1\right)$

$\frac{y}{z}=\frac{4}{5}...........\left(2\right)$

Multiply (1) and (2)

$\frac{x}{y}\times \frac{y}{z}=\frac{1}{7}\times \frac{4}{5}$

$\frac{x}{z}=\frac{4}{35}$

Now,

$x=\frac{4z}{35}$

$y=\frac{4z}{5}$

$x:y:z=\frac{4z}{35}:\frac{4z}{5}:z$

Multiplying with $\frac{35}{z}$

$x:y:z=4:28:35$