At a lunch stand, each hamburger has 50 more calories than each order of fries. if 2 hamburgers and 3 orders of fries have a total of 1700 calories, how many calories does a hamburger have?

The correct answer is 370. A system of equations can be used, where h represents the number of calories in a hamburger and f represents the number of calories in an order of fries. The equation 2 h plus 3 f equals 1,700 represents the fact that 2 hamburgers and 3 orders of fries contain a total of 1700 calories, and the equation h equals f plus 50 represents the fact that one hamburger contains 50 more calories than an order of fries. Substituting f plus 50 for h in 2 h plus 3 f equals 1,700 gives 2, parenthesis, f plus 50, close parenthesis, plus 3 f, equals 1,700. This equation can be solved as follows:

2 f plus 100 plus 3 f equals 1,700

5 f plus 100 equals 1,700

5 f equals 1,600

f equals 320

The number of calories in an order of fries is 320, so the number of calories in a hamburger is 50 more than 320, or 370.