Tina would like to melt down her existing gold jewelry to make a 20 ounce gold necklace that is 90% pure gold. After melting her jewelry, she is left with two batches. One batch is 75% pure. The other batch is 96% pure. How much of the 96% pure melted gold should Tina mix with the 75% pure melted gold to obtain 20 ounces of 90% pure gold?

A.

5.71 ounces

B.

7.00 ounces

C.

14.29 ounces

D.

13.00 ounces

Question

Charles

Mathematics

29 June, 12:47

Tina would like to melt down her existing gold jewelry to make a 20 ounce gold necklace that is 90% pure gold. After melting her jewelry, she is left with two batches. One batch is 75% pure. The other batch is 96% pure. How much of the 96% pure melted gold should Tina mix with the 75% pure melted gold to obtain 20 ounces of 90% pure gold?

A.

5.71 ounces

B.

7.00 ounces

C.

14.29 ounces

D.

13.00 ounces

+1

Answers (1)

Know the Answer?

Mariela · Answer 1

X = oz of 75% pure gold

y = oz of 96% pure gold

x + y = 20

0.75*x + 0.96*y = 20*0.90

by solving the system of equations we find

x = 5.71 oz

y = 14.29 pz