Question

An alloy is to contain copper and nickel in the ratio of 3 : 7. Find the amount ( in kg) of
copper required to be melted with 28 kg of nickel to from the alloy.

Answer 1

$\frac{copper}{nickel} = \frac{3}{7}$
for 28 kg of nickel
$\frac{3}{7} \times \frac{4}{4} = \frac{12}{28}$
Amount of copper is 12kg to be melted with nickel to form alloy.

Answer 2

copper/nickel = 3/7
for 28 kg of nickel
3/7 × 4/4 = 12/28
ok,I hope it help you