Aschool cafeteria makes cheese sauce for macaroni using 15 cups of swiss cheese and 17 cups of cheddar cheese perry tries to make the sauce for a family parties in 5 cups of swiss and 7 cups of cheddar is perry using the correct ratio

No, perry is not using the correct ratio.

Step-by-step explanation: The ratio used in the cafeteria is 15:17 if we calculate the quotient of these numbers, we have:

15/17 = 0.882

Now, the ratio that Perry is using is 5:7, the quotient now is:

5/7 = 0.713

You can see that the quotients are different, which means that the ratios are different.

Here we are dividing the number of cups of swiss cheese by the number of cups of cheddar cheese.

The fact that in the perry recipe the quotient is smaller, this means that in this recipe the swiss cheese has less presence than in the cafeteria recipe.

If you want to reduce the proportions, it is kinda hard because 17 is a prime number, so you won't have a whole number of cups of cheddar cheese.

so 15/3 = 5, this means that we also must divide 17 by 3.

Then, the correct ratio would be:

5:17/3

or 5:5.666