$70 \textbackslash\% \cdot 10=7$ $80 \textbackslash\% \cdot 20=16$ $90 \textbackslash\% \cdot 30=27$ Adding them up gets $7+16+27=50$. The overall percentage correct would be $\frac{50}{60}=\frac{5}{6}=5 \cdot 16 . \overline{6}=83 . \overline{3} \approx(\mathbf{D}) 83$. 
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) 
Options:
1) $$40$$ 
2) $$77$$ 
3) $$80$$ 
4) $$83$$ 
5) $$87$$ 