GAUSS8 1999 Problem 16

Past Contests GAUSS8 GAUSS (GR. 8) - 1999
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1

In a set of five numbers, the average of two of the numbers is 12 and the average of the other three numbers is 7. The average of all five numbers is

Answer Choices
A. 8\frac13
B. 8\frac12
C. 9
D. 8\frac34
E. 9\frac12