Question on Math Homework

Question

A jewelry store works with two types of precious metal, which are 34% and 62% gold. How much of the 62% gold should be added to the 7.5 grams of the 34%, so that the mixture contains 50% gold

Answer 1

gold concentrations:

34%(7.5 grams) + 62%(x grams) = 50%(7.5 + x grams)

 

.34(7.5) + .62x = .5(7.5+x)

 

2.55 + .62x = 3.75 + .5x

 

.62x - .5x = 3.75 - 2.55

 

.12x = 1.2

 

x = 10 grams