Let price of cheeseburger be x while price of a bag of chips be y hence for the case of Nathan, we can write the equation as x+y=3.75. Similarly, for Jack, we can write it as 2x+3y=8.25
x+y=3.75 hence x=3.75-y and substituting this into the second equation we have
2x+3y=8.25
2(3.75-y)+3y=8.25
7.5-2y+3y=8.25
y=8.25-7.5=0.75
x=3.75-y=3.75-0.75=3
Therefore, price of cheeseburger is $3 and chips is $0.75
