Question

zinc and copper are in the ratio of 5:3 in 200 gm of an alloy. how much grams of copper be added to make the ratio 3:5

Answer 1

let the amount of zinc be 'x'
let the amount of copper be 'y'
total amount is 200 grams
x+y=200---------1
given the ratio is
x/y=5/3
3x=5y------------2
multiply the equation 1 with 3 on both sides
3x+3y=600-----3
substitute equation 2 in equation 3
8y=600
y=75
x=125
let the required amount of copper be n
then 125/(n+75)=3/5
solve for n
we get 133.332