An alloy of copper is 10% copper and weighs 25 pounds. A second alloy is 18% copper. How much (to the nearest tenth lb.) of the

Question

Aloiza [94]

3 years ago

10

An alloy of copper is 10% copper and weighs 25 pounds. A second alloy is 18% copper. How much (to the nearest tenth lb.) of the

second alloy must be added to the first alloy to get a 13% mixture.

Mathematics

1 answer:

Alisiya [41] · Answer 1 · 2022-04-17T21:43:36+03:00

let the weight of the second alloy be y
convert the percentage to fraction, that is 10/100=0.1, 18/100=0.18, 13/100=0.13
Total weight if the mixture is 0.1 x 25+0.18y=0.13(25+y)
2.5+0.18y=3.25+0.13y
like terms together
0.18y +0.13y = 3.25-2.5
0.05y=0.75
divide both side by 0.05
Y is therefore 15 pound of 18% copper is needed