Let
y ---> total charge
m ---> number of miles
so
Company A
y=73 ------> equation A
Company B
y=0.90m+55 ----> equation B
Company A < Company B
The inequality that represents this situation is equal to
73 < 0.90m+55
solve for m
73-55 < 0.90m
18 < 0.90m
Rewrite
0.90m > 18