ExplanationUse smart numbers. There are 20% fewer boys than girls, so choose 100 for the number of girls (100 is a good number to pick for percent problems). Thus, there are (100)(0.8) = 80 boys in the school.
If 75% of all the boys take civics, then 0.75(80) = 60 boys take civics. If 48% of all the girls take civics, then 0.48(100) = 48 girls take civics.
Therefore, 60 + 48 = 108 students take civics and there are 180 total students:
\(\frac{108}{180} \times 100\%=60\%\)
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