Question

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?

Answer 1

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