Full-Length PSAT 10 Math Practice Test-Answers and Explanations
27- Choice D is correctPercent of cities in the type of pollution A: \(\frac{8}{10}×100=80\%\)Percent of cities in the type of pollution C: \(\frac{7}{10}×100=70\%\)Percent of cities in the type of pollution E: \(\frac{5}{10}×100=50\%\) 28- Choice D is correctLet x be the number of cities that need to be added to the type of pollutions E. Then:\(\frac{x+5}{9}=0.8→x+5=9×0.8→x+5=7.2→x=2.2\) […]
