Carlos Invested $10,000 at 7%, $20,000 at 6

Multiple Choice

Carlos invested $10,000 at 7%, $20,000 at 6.5%, and $50,000 at 5%. What is the average rate of interest earned by his investments?

A) 6.2%
B) 5.5%
C) 5.8%
D) 5.6%
E) 6.3%