Question

If x : y=4:5 and y:z=10:18, then x:z=?

Answer 1

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

Putting this value in second ratio,

$\frac{y}{z} = \frac{10}{18} \\ \frac{ \frac{5x}{4} }{z} = \frac{10}{18} \\ \frac{5x}{4z} = \frac{10}{18} \\ \frac{x}{z} = \frac{10}{18} \times \frac{4}{5} \\ \\ \frac{x}{z} = \frac{2 \times 4}{18} = \frac{4}{9}$

∴ x : z = 4 : 9

Hope It Helps :)