The best way to go about this is to use benchmark percentages.
For baseball, 25% of 800 people chose that, so we can do 800/4 to get 200, so 200 students chose baseball
For basketball, we could do 800/5 but that isn't mental math, so we can do 10% of 800 is 80 and 80*2=160. So 40 more kids chose baseball over basketball.
