Suppose a standard twelve-hour clock now shows a time of 10: 45 what time will the clock show in a 100 hour from now

It should show 2:45. You can use 12 hr increments to get you back to 10:45 and 12 goes into 100 nine times bringing it to 96. Because of that you have 4 more hours to add to 10:45 and that brings you to 2:45.

There are 24 hours in a day
100/24= 4 and 4/24

so you can cancel out the 4 days because in 4 days the time will be the same
so the 4/24 means that you add the 4 hours to the 10:45 to get
2:45 after 4 days

No solution : there is no number of boxes that she bought