Each ounce of Food I contains 3 g of carbohydrate and 2 g of protein, and each ounce of Food II contains 5 g of carbohydrate and 3 g of protein. Suppose x ounces of Food I are mixed with y ounces of Food II. The foods are combined to produce a blend that contains exactly 73 g of carbohydrate and 46 g of protein.
a. Explain why there are 3x + 5y g of carbohydrate in the blend and why we must have 3x + 5y = 73. Find a similar equation for protein. Sketch the graphs of both equations.
b. Where do the two graphs in part (a) intersect? Interpret the significance of this point of intersection

Therefore, the amount of carbohydrate in food 1 is 3x while that of food II is 5y. Since the blend contains exactly 73 g of carbohydrate, the total number of carbohydrate in both food I and food II is 73 g. Hence:

3x + 5y = 73 (1)

Food I contains 2 g of protein and food II 3 g of carbohydrate. Therefore, the amount of protein in food 1 is 2x while that of food II is 3y. Since the blend contains exactly 46 g of protein, the total number of protein in both food I and food II is 46 g. Hence:

2x + 3y = 46 (2)

Using geogebra to Sketch the graphs of both equations.

b) The point of intersection is gotten from the graph, this gives x = 11, y = 8.

The point of intersection shows the amount of food I and food II that give the required amount of protein and carbohydrate.

11 ounce of food I and 8 ounce of food II would produce the required amount of protein and carbohydrate