Answer: 275
Explanation:
Let the total number of hamburger be x and the total number of cheeseburgers be y. That is
x + y = 500 ................... equation 1
Since there were 50 fewer cheeseburgers sold than hamburgers, this means that the number of hamburgers sold is more than cheeseburgers by 50 , that is
x - y = 50 ............. equation 2
solving the resulting linear equation by substitution method;
From equation 2 , make x the subject of the formula , that is
x = 50 + y ................ equation 3
substitute equation 3 into equation 1 , we have
50 + y + y = 500
50 + 2y = 500
2y = 500 - 50
2y = 450
y = 450/2
y = 225
substitute y = 225 into equation 3 to find the value of x. we have
x = 50 + y
x = 50 + 225
x = 275
Therefore 275 hamburgers were sold