Answer:
84 ounces of pure gold
Step-by-step explanation:
Jess has 60 ounces of an alloy that is 40% gold. How many ounces of pure gold must be added to this alloy to create a new alloy that is 75% gold?
Pure gold = 100% gold
Let the number of ounces of pure gold = x
Hence, we have the equation
40% × 60 ounces + 100%× x ounces = 75%(60 + x)ounces
= 0.4 × 60 + 1x = 0.75(60 + x)
= 24 + x = 45 + 0.75x
Collect like terms
x - 0.75x = 45 - 24
0.25x = 21
x = 21/0.25
x = 84 ounces
Therefore, we need 84 ounces of pure gold
