A
80 + .6m
B
50 + .9m
after 10 miles A will be 86 and B will be 59
after 25 miles A will be 95 and B will be 72.5
after 60 miles A will be 116 and B will be 104
after 70 miles A will be 122 and B will be 113
after 85 miles A will be 131 and B will be 126.5
after 95 miles A will be 137 and B will be 135.5
after 100 miles A will be 140 and B will be 140
any number of miles over 100 in a day will make A a better deal than B