Aparking lot charges $1.50 for the first hour of of parking and 55 cents for each additional half hour. how much would it cost to park a car from 12: 45p. m.to 6: 15p. m?

$5.90
because the first hour would be till 1:45 p.m. which would cost 1.50, so you put those numbers aside.
so now, you work with 1:45 p.m to 6:15 p.m.
just to make it look easier to look at, you can add the 15  extra minutes from 6:15, to 1:45,
so now, you work with whole times, 2 p.m and 6 p.m.
continuing, you find the difference between the two. 6-2= 4 hour difference.
In an hour(60minutes) there are 2 (30minutes). ---> 30mins.*2 = 60mins.
so you take the 4 hours, and multiply it by 2 to find the amount of 30 minutes there are in 4 hours 4*2= 8
Now, you multiply 0.55 (the cost for every extra 30 minutes) and 8 (the number of 30 extra minutes in the extra time) = 4.40
You then add 4.40 and 1.50 ( for the first hour) and get $5.90