Question

2) How much PURE copper must be added to 50.255kg of an allow containing 12% copper

to raise the copper content to 21%

Answer 1

let x=amt of pure copper to add:

12%*50+100%x=21%(50+x)

6+x=10.5+.21x

.79x=4.5

x=5.7

amt of pure copper to add: 5.7 kg

Explanation: