The dependent variable is f(m)...total money earned per day the independent variable is m...number of miles
f(m) = 3.5m + 65
for 40 miles.. f(40) = 3.5(40) + 65 = 140 + 65 = 205 <== money earned for the day ======================== the dependent variable is f(p)....total charged the independent variable is p...the number of pounds
f(p) = 3.5p
for 5 lbs... f(5) = 3.5(5) f(5) = 17.50 <== total that was charged