Question

A metalworker has a metal alloy that is 25​% copper and another alloy that is 70​% copper. How many kilograms of each alloy should the metalworker combine to create 50 kg of a 61​% copper​ alloy? The metalworker should use nothing kilograms of the metal alloy that is 25​% copper and nothing kilograms of the metal alloy that is 70​% copper

Answer 1

40

Explanation:

Answer 2

10 kgs of 25% copper alloy and 40 kgs of 70% copper alloy

Explanation:

Let a be kg of 25% copper alloy, and

b be kg of 70% copper alloy

We can write two equations:

1. a + b = 50

2. 0.25a+0.7b=0.61(50)

We can write #1 as b = 50 - a, and then plug it into #2. We have:

0.25a+0.7b=0.61(50)

0.25a+0.7(50 - a) = 0.61(50)

0.25a + 35 - 0.7a = 30.5

-0.45a = 30.5 - 35

-0.45 a = -4.5

a = -4.5 / - 0.45

a = 10

Also, b = 50 - a, so b = 50 - 10 = 40

The metalworker should use 10 kgs of 25% copper alloy and 40 kgs of 70% copper alloy to make it.