ANSWER
225 hamburguers
Step-by-step explanation
First, we have to name the variables:
• x: number of hamburgers sold
,
• y: number of cheeseburgers sold
We know that they sold a total of 503, so one of the equations is x + y = 503.
Also, we know that the number of cheeseburgers is 53 more than the number of hamburgers, so the other equation is y = x + 53.
We have to solve the system,

Since we have to solve for x, we can use the substitution method. Replace y with the second equation in the first equation,

Add like terms,

Subtract 53 from both sides,

And divide both sides by 2,

Hence, 225 hamburgers were sold on Tuesday.