选择题
2006 AMC 8 Problem 12: Combined Test Score
Antonette gets 70% on a 10-problem test, 80% on a 20-problem test, and 90% on a 30-problem test. If the three tests are combined into one 60-problem test, which percent is closest to her overall score?
A.
40
B.
77
C.
80
D.
83
E.
87