Antonette gets $70 \textbackslash\%$ on a 10 -problem test, $80 \textbackslash\%$ on a 20 -problem test and $90 \textbackslash\%$ on a 30 -problem test. If the three tests are combined into one 60 problem test, which percent is closest to her overall score? (2006 AMC 8, Question \#12) 
选项为:A:$$40$$  B:$$77$$  C:$$80$$  D:$$83$$  E:$$87$$  请回答其中一个选项.