Three friends eat lunch together. if the bill comes to $21 plus 10% of tax, how much will each person owe

So first you have to multiply 21 by. 1 to figure out ten percent

you then get 2.1

you add 21 and 2.1 together and get 23.1

then since you have 3 people you divide by 3 and get 7.7

therefor 7.7 is your answer