You will set the equation up as part/whole = percent/100 and when you replace it with your numbers you get 60/x = 80/100 now you cross multiply and do 60*100 = 80 * x and you get 6,000 = 80x now you divide both sides by 80 then you get 75 was the original price
100% of the people present would be 60.
Answer: it is called the slope intercept
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