Question

If $a:b=5:6$ and $b:c=8:9$, find $a:c$

Answer 1

$a:b=5:6$

$⟹\frac{a}{b}=\frac{5}{6}$

$⟹a=\frac{5}{6}b$ - ( 1 )

$Also,b:c=8:9$

$⟹b=\frac{8}{9}c$ - ( 2 )

From ( 1 ) and ( 2 ), we get,

$a=\frac{5}{6}\left(\frac{8}{9}c\right)$

$⟹\frac{a}{c}=\frac{20}{27}$

$⟹a:c=20:27$