A metal worker has a metal alloy that is 20% copper and another alloy that is 75% copper. How many kilograms of each alloy should the metal worker combine to create 90 kg of a 64% copper alloy?

he needs to combine 18 kg

of the 20% copper alloy and 72 kg of the 75% copper alloy.

Step-by-step explanation:

Let x represent the number of kilograms of the 20% copper alloy that he needs to use.

Let y represent the number of kilograms of the 75% copper alloy that he needs to use.

The mass of the copper to be created is 90 kg. It means that

x + y = 90

The amount copper in the first alloy is 20/100 × x = 0.2x

The amount copper in the second alloy is 75/100 × y = 0.75y

The amount of copper in the alloy to be created is

64/100 × 90 = 57.6

The equation would be

0.2x + 0.75y = 57.6- - - - - -- - - - - 1

Substituting x = 90 - y into equation 1, it becomes

0.2(90 - y) + 0.75y = 57.6

18 - 0.2y + 0.75y = 57.6

- 0.2y + 0.75y = 57.6 - 18

0.55y = 39.6

y = 39.6/0.55

y = 72

x = 90 - y = 90 - 72

x = 18

point a is the center of the circle that passes through points e, f, and g and the center of the circle that passes through points x, y, and z.

the answer is thin because within context, the stanza concludes the and frail tone the people have toward each other, and the fact that it would be thin, makes the most sense compared to "pliable" or "not hard or firm to the touch". hope this , good luck.

step-by-step explanation:

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