Looks like you are missing a fraction after the 'If'
In this case you can say in one hour Austin earns $7.50.
Answer:

Step-by-step explanation:
we know that
<u><em>Combinations</em></u> are a way to calculate the total outcomes of an event where order of the outcomes does not matter.
To calculate combinations, we will use the formula

where
n represents the total number of items
r represents the number of items being chosen at a time.
In this problem

substitute

simplify




279ft/9sec = xft/1sec
Cross multiply to get
9x = 279 divide by 9
x = 31
31 feet per second
An arithmetic sequence starts with one number and you add the common difference to the previous term to get the current term
So...
f(x)=mx+b
m=common difference
b=starting point
f(11)=125=11m+b
-
f(1)=5=1m+b
--------
120=10m
Divide both sides by 10
12=m
Your common difference is 12.