Problem 1
You have the correct y value, but it refers to pizzas (not salads).
If you need to convert to a mixed number, then follow these steps.
27.2 = 27 + 0.2
27.2 = 27 + 1/5
27.2 = 27 & 1/5
27.2 pizzas is the same as 27 & 1/5 pizzas. In other words, you have 27 whole pizzas plus 1/5 of an extra one.
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Problem 2
This is correct.
The decimal 1.75 converts to the mixed number 1 & 3/4 because of the steps below.
1.75 = 1 + 0.75
1.75 = 1 + 3/4
1.75 = 1 & 3/4
In my opinion, it is optional to convert to a mixed number for either problem 1 or problem 2. So you can stick with 1.75 as the answer if you want.
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Problem 3
16 & 3/4 = 16 + 3/4 = 16 + 0.75 = 16.75
To get the unit rate, which is the cost per unit, we divide the total cost over the amount.
cost/amount = (2.89)/(16.75) = 0.1725373
which is approximate.
Round to the nearest penny to get a unit cost of $0.17 per fluid ounce, i.e. a unit cost of 17 cents per fluid ounce.
Answer: $0.17 or 17 cents
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Problem 4
We follow the same idea as problem 3.
4 & 3/5 = 4 + 3/5 = 4 + 0.6 = 4.6
unit cost = (total cost)/(amount)
unit cost = (7.56)/(4.6)
unit cost = 1.643478 dollars approximately
unit cost = 1.64 dollars approximately
Answer: $1.64
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Problem 5
6 & 1/2 = 6 + 1/2 = 6 + 0.5 = 6.5
Like before, we'll divide the total cost over the total amount.
unit cost = (total cost)/(amount)
unit cost = (8.22)/(6.5)
unit cost = 1.264615 dollars approximately
unit cost = 1.26 dollars approximately
Answer: $1.26
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Here's another way to look at the unit cost or unit rate.
Notice in problem 5 it says "cost per yard". This is the same as "cost per 1 yard" or "cost for each yard".
We can express the given info as the ratio
6.5 yards:$8.22
Now we want the "6.5 yards" to become "1 yard" to achieve the unit rate.
So we'll divide both parts by 6.5
6.5 yards:$8.22
6.5/6.5 yards:$8.22/6.5
1 yard: $1.26 approximately
For each yard, we'll spend $1.26
Problems 3 and 4 follow similar ideas. So this is why we divided the total cost over the total amount.