So, the number of chips Dregg eat was 22.
Explanation
Suppose, the number of potato chips is [tex]x[/tex]
As each chip had 12 calories, so the total calories in [tex]x[/tex] number of chips [tex]=12x[/tex]
The hamburger had 375 calories and the meal had total 639 calories. So, the equation will be .......
[tex]12x+375= 639\\ \\ 12x= 639-375=264\\ \\ x=\frac{264}{12}=22[/tex]
So, the number of chips Dregg eat was 22.
