To determine the number of salads sold, write and solve a system of two equations. Let x equal the number of salads sold and let y equal the number of drinks sold. Since the number of salads plus the number of drinks sold equals 209, the equation
x+y=209 must hold. Since each salad cost
6.50, each soda cost 2.00, and the total revenue was
$836.50, the equation
6.50x+2.00y=836.50 must also hold. The equation x + y = 209 is equivalent to 2x + 2y = 418, and subtracting each side of
2x+2y=418 from the respective side of
6.50x+2.00y=836.50 gives
4.5x=418.50. Therefore, the number of salads sold, x, was
x==93.Choices A, C, and D are incorrect and could result from errors in writing the equations and solving the system of equations. For example, choice C could have been obtained by dividing the total revenue,
$836.50, by the total price of a salad and a soda,
$8.50, and then rounding up.