Tonya went out to a restaurant for lunch. she tipped 12% of her bill, which brought the sum of the lunch bill plus the tip to $28. how much was the original bill?

112% of original=28

percent measn parts out of 100

112%=112/100=1.12

'of' means multiply

112% of original=28 means

1.12 times original=28

divide both sides by 1.12

original=25

original bill was $25