How many ounces of a silver alloy that costs $5.50 per ounce should be mixed with one that costs $7.00 per ounce to make a new 30 ounce alloy that costs $6.40 per ounce?

135.73 ounces of a silver alloy that costs $5.50 per ounce should be mixed.

Step-by-step explanation:

Given:

A silver alloy that costs $5.50 per ounce should be mixed with one that costs $7.00 per ounce to make a new 30 ounce alloy that costs $6.40 per ounce.

Now, to find the ounces of silver alloy.

Let the silver costs $5.50 per ounce be

And the silver costs $7.00 per ounce be

So, the total ounce make a new alloy:

 ....(1)

Now, the total costs of silver alloy:

Putting the value of from equation (1) in the place of :

Subtracting both sides by 210 we get:

Dividing both sides by -1.5 we get:

Therefore, 135.73 ounces of a silver alloy that costs $5.50 per ounce should be mixed.

dont think so

step-by-step explanation: