A metalworker has a metal alloy that is 20% copper and another alloy that is 75% copper. How many kilograms of each alloy should the metalworker combine to create 60kg of a 53% copper alloy?

Answer 1

x + y = 60, x = 60 - y

(20)x + (75)y = (60(53)

Substitute:

(20)(60 - y) + (75)y = (60(53)

1200 - 20y + 75y = 3180

55y = 1980

y = 36 kg

x = 24 kg