The answer is a. $1.75 + $0.25x ≤ $15; x ≤ 53 miles
x - the number of miles
C - the cab charge
A cab charges $1.75 for the flat fee and $0.25 for each mile: C = 1.75 + 0.25x.
Eddie has $15 to spend. So, he cannot spend more than 15 on the cab and the maximum amount he can spend is 15. Therefore:
1.75 + 0.25x ≤ 15
Now, let's solve it:
0.25x ≤ 15 - 1.75
0.25x ≤ 13.25
x ≤ 13.25 / 0.25
x ≤ 53