How many Plain Burgers and Cheeseburgers Did Bob's Burgers Sell?

Calculation:

Total Sales:
Let the number of plain burgers be P and the number of cheeseburgers be C.
Total Sales: 8P + 10C = 300

Number of Cheeseburgers Sold:
They sold 3 more cheeseburgers than plain burgers.
C = P + 3

Substitute C in the total sales equation:
8P + 10(P + 3) = 300
8P + 10P + 30 = 300
18P + 30 = 300
18P = 270
P = 15

Substitute P back into C = P + 3:
C = 15 + 3
C = 18

Therefore, Bob's Burgers sold 15 plain burgers and 18 cheeseburgers.