**Units of Time:**
1 minute = 60 seconds
1 hour = 60 minutes
1 hour = 3,600 seconds
**When to Use Seconds:** Racing, quick activities (blinking, switching lights, snapping fingers) — shows precise time differences.
**When to Use Minutes:** Homework, painting, filling water — medium-length activities.
**When to Use Hours:** School events, picnics, yoga practice — longer activities.
**12-Hour vs 24-Hour Format:**
a.m. = morning (12:00 a.m. to 11:59 a.m.)
p.m. = evening (12:00 p.m. to 11:59 p.m.)
To convert p.m. to 24-hour: Add 12 (e.g., 2:30 p.m. = 14:30 hours)
To convert 24-hour after 12:00 back to p.m.: Subtract 12 (e.g., 20:45 = 8:45 p.m.)
**Converting Time:**
Hours to minutes: Multiply by 60 (e.g., 2 hr = 2 × 60 = 120 min)
Minutes to seconds: Multiply by 60 (e.g., 5 min = 5 × 60 = 300 sec)
Minutes to hours: Divide by 60 (e.g., 150 min = 2 hr 30 min)
Seconds to minutes: Divide by 60 (e.g., 320 sec = 5 min 20 sec)
**Finding Elapsed Time:** End time − Start time = Time taken
**Don't Confuse:** 12:30 a.m. is midnight area (very early); 12:30 p.m. is afternoon (after lunch).
Q1. How many seconds are there in 3 minutes?
Answer: A — 3 minutes × 60 seconds per minute = 180 seconds.
Q2. Raghav took 1 hour 20 minutes to paint a picture. How many minutes is this?
Answer: B — (1 × 60) + 20 = 60 + 20 = 80 minutes.
Q3. What is 05:30 p.m. in 24-hour format?
Answer: B — Add 12 to afternoon times: 5:30 p.m. + 12 = 17:30 hours.
Q4. Raghu left his house at 08:00 and reached his Nana ji's house at 09:05. How long did the journey take?
Answer: B — From 08:00 to 09:00 is 1 hour, plus 5 more minutes to 09:05 = 1 hour 5 minutes.
Q5. How many hours and minutes is 150 minutes?
Answer: B — 150 ÷ 60 = 2 with remainder 30, so 2 hours 30 minutes.
Q6. Which activity would you measure in seconds?
Answer: C — Snapping fingers is a very quick action that happens in just a few seconds, so we use seconds to measure it precisely.
Q7. If Jyoti went to play at 06:15 p.m. and came back after 1 hour 45 minutes, what time did she reach home?
Answer: C — 06:15 p.m. + 1 hour = 07:15 p.m.; then 07:15 p.m. + 45 minutes = 08:00 p.m.
Q8. Convert 220 minutes into hours and minutes.
Answer: B — 220 ÷ 60 = 3 remainder 40;
Q9. Ragini finished her homework at 09:40 p.m. and it took 1 hour 10 minutes. When did she start?
Answer: A — Work backward: 09:40 p.m. − 1 hour = 08:40 p.m.; then 08:40 p.m. − 10 minutes = 08:30 p.m.
Q10. Look at the clock image. The seconds hand is at 12 and the minute hand is at 2. How many seconds have passed?
Answer: A — When the minute hand points to 2, that represents 10 minutes on the minute scale, but since we're asked about seconds and the seconds hand is at 12, we count: the minute hand at 2 means 10 minutes, so 0 seconds have passed in the current minute; if asking total, each number = 5 minutes, but for seconds: each number = 5 seconds, so minute hand at 2 = 10 seconds mark.
How many seconds are in 1 minute?
1 minute = 60 seconds.
If Raghav started yoga at 06:00 and finished at 07:20, how long did he practice?
From 06:00 to 07:20 is 1 hour and 20 minutes.
Convert 180 minutes into hours.
180 minutes ÷ 60 = 3 hours.
What is the 24-hour format for 02:30 p.m.?
02:30 p.m. = 14:30 hours (add 12 to afternoon times).
What is the 12-hour format for 20:45 hours?
20:45 hours = 08:45 p.m. (subtract 12 from times after 12:00).
How many minutes is 2 hours 45 minutes?
(2 × 60) + 45 = 120 + 45 = 165 minutes.
Jyoti went to play at 06:15 p.m. and came back after 1 hour 45 minutes. What time did she return?
06:15 p.m. + 1 hour 45 minutes = 08:00 p.m.
Convert 320 seconds into minutes and seconds.
320 ÷ 60 = 5 minutes and 20 seconds (since 5 × 60 = 300, and 320 − 300 = 20).
When is seconds used instead of minutes to measure time?
Seconds are used for short time durations like races, quick activities, or precise measurements.
If lunch break starts at 12:30 p.m. and lasts 35 minutes, when does it end?
12:30 p.m. + 35 minutes = 01:05 p.m.
How many seconds are in 5 minutes? [1 mark]
Use the rule: 1 minute = 60 seconds. Multiply 5 by 60.
Fill in the blanks: (i) 1 hour 10 minutes = _____ minutes (ii) 75 minutes = _____ hour _____ minutes [2 marks]
For (i): Convert 1 hour to 60 minutes, then add 10. For (ii): Divide 75 by 60 to find the hour; the remainder is minutes.
Raghav studies 4 subjects, spending 50 minutes on each. Find the total time taken in hours and minutes. Explain your strategy. [3 marks]
Step 1: Find total minutes = 4 × 50 = 200 minutes. Step 2: Convert 200 minutes to hours and minutes by dividing by 60 (200 ÷ 60 = 3 remainder 20).
A group of children left for a picnic at 08:30 a.m. They returned after 4 hours and 10 minutes. (i) At what time did they return? (ii) Convert this return time to 24-hour format. (iii) How many minutes was the picnic duration? Show all steps. [5 marks]
Step 1: Add 4 hours 10 minutes to 08:30 a.m. (Add hours first: 08:30 + 4 hours = 12:30; then add 10 minutes = 12:40 p.m.). Step 2: Convert 12:40 p.m. to 24-hour format (add 12: 12 + 12 = 24, so it becomes 00:40, but noon times stay as 12:40 hours). Step 3: Convert 4 hours 10 minutes to minutes = (4 × 60) + 10 = 240 + 10 = 250 minutes.
True or False: 12:30 a.m. and 12:30 p.m. are the same time. Give a reason. [2 marks]
12:30 a.m. is after midnight (very early morning, around 12:30 in the night). 12:30 p.m. is after noon (afternoon). They are 12 hours apart.
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