420
10 hours and 30 minutes.
8:00am is eight hours, 8:00pm is twenty hours (20:00). 12:00am is zero hours (00:00), 12:00pm is twelve hours. 12:30am is thirty minutes (00:30), 12:30pm is twelve hours and thirty minutes. 4:30am is four hours and thirty minutes, 4:30pm is sixteen hours and thirty minutes (16:30).
About $43,200
Convert everything to hours, or everything to minutes, then multiply. In this case, it is easier to convert everything to hours - 15h30m = 15.5 hours.
If Lawrence walked twelve miles in six hours, he was walking two miles per hour. In 30 minutes he would have walked one mile.
Twelve hours
$150 x 6 hours = $900.00
8 hours
The duration of His Last Twelve Hours is 1.35 hours.
The duration of Twelve Hours to Kill is 1.38 hours.
The duration of Twelve Crowded Hours is 1.07 hours.
c = 5+ 3*h