Question

If A : B = 3 : 5 and B : C = 4 : 7 , find A: B : C

Answer 1

$\frac{A}{B}=\frac{3}{5}=\frac{12}{20}$ (Multyplying numerator and denominator by 4)
$\frac{B}{C}=\frac{4}{7}=\frac{20}{35}$ (Multiplying numerator and denominator by 5)
SO, A:B:C = 12:20:35