Let’s solve each elapsed time problem step by step.
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Problem 1: Start Time = 1:15 a.m., End Time = 2:30 p.m.
We need to find how much time passes from 1:15 in the morning to 2:30 in the afternoon.
Step 1: From 1:15 a.m. to noon (12:00 p.m.)
→ That’s 10 hours and 45 minutes.
(From 1:15 to 12:15 is 11 hours, but we only go to 12:00, so subtract 15 min → 10h 45m)
Actually, let’s do it more carefully:
From 1:15 a.m. to 12:15 p.m. is exactly 11 hours.
But end time is 2:30 p.m., which is 2 hours 15 minutes after 12:15 p.m.? No — better to break into parts.
Better approach:
From 1:15 a.m. to 12:00 p.m. (noon):
- 1:15 a.m. to 12:15 p.m. = 11 hours
- But we stop at 12:00 p.m., so subtract 15 minutes → 10 hours 45 minutes
Then from 12:00 p.m. to 2:30 p.m. = 2 hours 30 minutes
Total = 10h 45m + 2h 30m = 13 hours 15 minutes
Wait — let me double-check with another method.
Alternative: Convert both times to minutes past midnight.
1:15 a.m. = 1 hour 15 min = 75 minutes past midnight
2:30 p.m. = 14 hours 30 min = 870 minutes past midnight
Elapsed = 870 - 75 = 795 minutes
795 ÷ 60 = 13 hours and 15 minutes →
✔ Correct.
So Problem 1:
13 hours 15 minutes
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Problem 2: Start Time = 9:30 a.m., End Time = 11:15 p.m.
Convert to minutes past midnight:
9:30 a.m. = 9*60 + 30 = 570 minutes
11:15 p.m. = 23*60 + 15 = 1380 + 15 = 1395 minutes
Elapsed = 1395 - 570 = 825 minutes
825 ÷ 60 = 13 hours and 45 minutes →
✔
Check manually:
From 9:30 a.m. to 9:30 p.m. = 12 hours
From 9:30 p.m. to 11:15 p.m. = 1 hour 45 minutes
Total = 12 + 1h45m = 13h45m →
✔
Problem 2:
13 hours 45 minutes
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Problem 3: Start Time = 8:15 a.m., End Time = 11:30 p.m.
Minutes past midnight:
8:15 a.m. = 8*60 + 15 = 495 minutes
11:30 p.m. = 23*60 + 30 = 1380 + 30 = 1410 minutes
Elapsed = 1410 - 495 = 915 minutes
915 ÷ 60 = 15 hours 15 minutes →
✔
Manual check:
From 8:15 a.m. to 8:15 p.m. = 12 hours
From 8:15 p.m. to 11:30 p.m. = 3 hours 15 minutes
Total = 12 + 3h15m = 15h15m →
✔
Problem 3:
15 hours 15 minutes
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Problem 4: Start Time = 8:45 a.m., End Time = 10:30 p.m.
Minutes past midnight:
8:45 a.m. = 8*60 + 45 = 525 minutes
10:30 p.m. = 22*60 + 30 = 1320 + 30 = 1350 minutes
Elapsed = 1350 - 525 = 825 minutes
825 ÷ 60 = 13 hours 45 minutes →
✔
Manual check:
From 8:45 a.m. to 8:45 p.m. = 12 hours
From 8:45 p.m. to 10:30 p.m. = 1 hour 45 minutes
Total = 12 + 1h45m = 13h45m →
✔
Problem 4:
13 hours 45 minutes
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Final Answer:
1. 13 hours 15 minutes
2. 13 hours 45 minutes
3. 15 hours 15 minutes
4. 13 hours 45 minutes
Parent Tip: Review the logic above to help your child master the concept of time elapsed worksheet 3rd.
