Help please ! will mark brainliest
Dr. Hamilton took an alloy containing 40%
silver and mixed it with an alloy containing
60% silver to get an 80-ounce alloy con-
taining 45% silver. How many ounces of
the 40% alloy did he use?

he used 60 ounces of

the 40% alloy.

Step-by-step explanation:

Let x represent the number of ounces of alloy containing 40%

silver that was used.

Let y represent the number of ounces of alloy containing 60%

silver that was used.

The weight of the alloy made is 80 ounces. It means that

x + y = 80

The amount of silver contained in the first alloy is 40/100 × x = 0.4x

The amount of silver contained in the second alloy is 60/100 × x = 0.6x

The amount of silver contained in the mixture is 45/100 × 80 = 36

Therefore,

0.4x + 0.6y = 36- - - - - - - - - - - - -1

Substituting x = 80 - y into equation 1, it becomes

0.4(80 - y) + 0.6y = 36

32 - 0.4y + 0.6y = 36

- 0.4y + 0.6y = 36 - 32

0.2y = 4

y = 4/0.2

y = 20

x = 80 - 20

x = 60

a variable is any characteristics, number, or quantity that can be measured or counted. a variable may also be called a data item. hope i !

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step-by-step explanation: