A horse stable keeps 12 horses. Each horse eats 2 pounds of oats per day over a 2-day weekend. The same horses will be staying for 3 additional days. The stable manager estimates that the stable should have at least 7 pounds of oats for each horse for the 5 days.

What mistake did the manager make?

The manager did not make a mistake. The estimate is correct.
The manager calculated the amount of oats for 7 days instead of 5.
The manager calculated the rate per day for 1 horse instead of 12.
The manager estimated the remaining days at 1 pound per day instead of 2 pounds per day.
The manager determined that the horses received 1 pound per day for the first two days instead of 2 pounds per day for the first two days.

The manager calculated the amount of oats for 7 days instead of 5.

Bruce's function:

Felicia's function:

Bruce's tiles cover more area

Step-by-step explanation:

Functions

We need to compare the area covered by tile of both Bruce and Felicia. We are required to find the function y, the area covered by the number of tiles he used, x.

We know the tiles used by Bruce cover 1/4 of a square foot, this is written as:

To find the function for Felicia, we must use the data provided in the table

For example,  

For x=9 tiles, y=1 sq ft

For x=18 tiles, y=2 sq ft

If we set

We can find the value of k

Thus

Testing the constructed function with x=18 and x=27

The function is complete and accurate.

Comparing both functions we see that Bruce's tiles cover more area because