Lunch is $2.74 per day. If x represents the number of days, then the total lunch bill will be $2.74x.
Here we are told that the total lunch bill is $58.19.
Then $2.74x = $58.19. Divide both sides by $2.74 to obtain the value of x (the number of lunch days).
x = $58.19/$2.74 = 21.2. Round this off to 21.
$58.19 will pay the total cost of 21 lunches, with a few cents left over.