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