The Unit Rate is the start of the slope/the y-intercept of the slope.To find that we need to make the slope first.
(shown in the first picture)
We can see that the slope is a linear function/a straight line, and if we just follow the line down the slope we can see that it has a y-intercept/unit rate of 2/3 of 1 whole.
(the second picture)
Provided his $100 budget is for millage only
100/22= $4.54 per day for miles
4.54/0.27= 16.835 miles per day
You’re answer is 21
7(3)= 21 I hope I’m right :))