Question

An alloy of zinc and copper contains the metals in the ratio 5 : 3. the quantity of zinc to be added to 6 kg of the alloy so that the ratio of the metal may be 3 : 1 is:

Answer 1

let Zink=5A,
copper=3A,

(5A+6)/3A =3/1,

5A+6=9A,

then
4A=6,

A=6/4=1.5,

hence
zinc=5×1.5=7.5 kg,
copper=3×1.5=4.5 kg