math
posted by jim .
a parking lot charges $1.50 for the first hour of parking and 55 cents for each additional half hour how much would it cost to park a car from 12:45pm to 6:15 pm

12:45  6:15 = 5.5 hours
That's 1 hour plus 9 additional halfhours. 
12:45pm  6:15pm  is 6Hr 30Min
or
6hr 1half hr...
less 1 hr at 1.50$ leaving 5hr and 1 half hour
5 full hr x 2 half hours/hr = 10half hrs + 1 half hr = 11 half hr
11 half hr @ .55 cents = 6.05$
6.05$ for 11 half hrs + 1.50$ for the initial hour = 7.55$