Answer:
9.5
Step-by-step explanation:
multiply 12.4 by 2 and then subtract the product from 43.8 then divide the new product by 2 to find 9.5
the answer is C because if you and it and then subtract it from all your answers than it would be C:$350
x = amount of the first alloy
y = amount of the second alloy
we know the first alloy is 25% copper, so then there is (25/100) * x of copper in it, namely 0.25x.
likewise, we know the second alloy is 75% copper so then there is (75/100) * y of copper or 0.75y.
he needs a 60 kgs mixture that 65% copper, or (65/100) * 60 = 39.

