Solution :
Give that a shark can chase prey about 30 miles per hour.
1 hour = 60 minute
by using unitary method, we will convert miles per hour into miles per minute
in 60 minutes the shark can chase the prey 30 miles
In 1 minute the shark can chase 
Hence the shark can chase the prey about 0.5 miles per minute.
Answer:
Only C is a function
Step-by-step explanation:
To test whether a graph is a function you use the vertical line test.
If you can place a vertical line anywhere on the plane (in the domain of the "function" to be tested) and it intersects the curve at more than one point, the curve is not a function.
We see with A, wherever we put the vertical line it intersects twice.
With B, it intersects infinitely many times.
C is a function because wherever we put the vertical line, it only intersects once.
D is a function because it intersects twice providing we do not put it on the "tip" of the parabola.
The mathematical reasoning behind this is that a function must be well-defined, that is it must send every x-value to one specific y-value. There can be no confusion about where the function's input is going. If you look at graph B and I ask you what is f(3)? Is it 1? 2? 3? ... Who knows, it's not well-defined and so it's not a function. However if I ask you about C, whichever input value for x I give you, you can tell me to which y-value it gets mapped/sent to.
Profit = Income - cost
Profit = 10s - (28 + 3s) = 10s - 28 -3s = 7s - 28.
Profit = 0
0 = 7s - 28
7s = 28
7s = 28/7
s = 4. This is the breakeven point.
Carlota must sell more than 4 shirts to make a profit
The way you have it is correct because root 2 is roughly 1.4 pi approximately is 3.4 and 4.5 is a rational number