Question

19. What is the elapsed time between 2:16 A.M. and 8:10 P.M.?
A. 17 hr. 54 min.
B. 29 hr. 54 min.
C. 18 hr. 18 min.
D. 22 hr. 18 min.

Answer 1

Firstly, you kinda want to "convert" the 2:16 am into pm as well, so to make it 2:16 pm, you will have to add 12 hours, so just remember that.
So now you want to find the time difference between 2:16 pm and 8:10 pm. The nest best thing to do would be to find the number of minutes to 3 pm first, and from three pm you know that 8:10 pm is 5:10 more, so now you can add 5:10 plus your 12 hours from before plus the number of minutes it takes to get from 2:16 pm to 3 pm to get your final answer

Answer 2

@FireKat97 thank u

Answer 3

No problem :)

Answer 4

I would do it slightly differently: it's 44 minutes to take you to the next hour (3AM). Then to get to the 8:00 PM hour, you have 9 hours to noon, and 8 more to 8 PM. Then another 10 minutes to get to 8:10 PM. 44 minutes + 10 minutes + 9 hours + 8 hours.

Similar approach would be to just add hours to the start time until you get to or past the finish time, then subtract however many extra minutes you had. For example to go from 3:47 AM to 5:15 PM would be 12 hours to 3:47 PM, 2 more to 5:47 PM, and then subtract 47-15=32 minutes from the total, giving 14 hours - 32 minutes or 13 hours and 28 minutes.

Key is to choose a method that you can use without mistakes and get some practice.

Answer 5

@fireKat97 @whpalmer4 i came up with (C) 18hr .18min. am i rite??

Answer 6

no - that is not correct

you can check by adding that to 2:16.

these things are easier in the 24Hour notatin
8:10 pm is 20:10

Answer 7

@thuggmyssess
Unfortunately, (C) is not the correct choice. You can see this just by looking at the minutes: if you are starting at 16 minutes after the hour, and you add some number of hours, you still have a time that is 16 minutes after the hour, just a different hour, right? And then when you add on some minutes, that is going to change the number of minutes after the hour. You started with 16 minutes after the hour, and with your proposed answer choice of (C) 18 hours 18 minutes, you add 18 minutes to the number of minutes after the hour, and by my calculation, that takes you to 16 + 18 = 34 minutes after the hour. Problem is that you want to end up at 10 minutes after the hour, not 34! So, that answer cannot be correct.

I agree with MrNood that working these problems as 24 hour times can make them somewhat easier, but you do have to do them as separate numbers for hours and minutes, and understanding how to do it in the fashion that I described is more convenient when the two times are not from the same day, such as "find the amount of time between 1:37 PM on Tuesday and 8:15 AM Thursday" for example.

To convert to 24 hour format, you simply add 12 to the hour if the time is after noon. 1:23 PM becomes 13:23, 7:18 AM becomes 7:18, etc. If you add 2 24 hour times and the minutes amount is 60 or greater, you subtract 60 from the minutes and add 1 to the hours. If you subtract 2 24 hour times and the minutes amount is less than 0, you add 60 to the minutes and subtract 1 from the hours.

Answer 8

@whpalmer4 and i didn't wind up choosing that answer i chose (A) 17 HR, 54 MIN)

Answer 9

thank the both of you