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How many pounds of a 23% zinc alloy must be mixed with a 42% zinc alloy to make 516 pounds of a 37.25% zinc alloy?

How many pounds of a 23 zinc alloy must be mixed with a 42 zinc alloy to make 516 pounds of a 3725 zinc alloy class=

Respuesta :

Answer:

(A)129 Pounds

Step-by-step explanation:

Let x be the number of 23% zink alloy

Therefore:

Since the total result is 516 pounds

The number of pounds of 42% zink alloy =516-x pounds

We then have the resulting equation:

0.23x+0.42(516-x)=0.3725*516

0.23x+216.72-0.42x=192.21

Colect like terms

0.23x-0.42x=192.21-216.72

-0.19x=-24.51

Divide both sides by 129

x=129 pounds

Therefore, the number of pounds of 23% zink alloy that must be mixed is 129 pounds.

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