The bill for lunch was 24.50 mr smith add a 20% tip how much did mr smith pay

First we have to find out what 20% of 24.5 is. because in math of means multiply we can multiply

24.5 times 0.2=4.9

now lets add that to the original number

24.5+4.9=29.4

it total he payed 29.4 dollars