Practice B

Show your thinking; use diagrams when they help. Do not open solutions during your first attempt.

1. A1

   Convert 1 min 15 s into seconds.

   Reveal explanation

   Answer: 75 s

   Each minute contains 60 seconds. 1 × 60 + 15 = 75 seconds.

2. A2

   How many minutes pass from 1:25 p.m. to 2:30 p.m.?

   Reveal explanation

   Answer: 65 min

   Count from 1:25 p.m. to the next whole hour, then onward to 2:30 p.m.. The intervals add to 65 minutes.

3. A3

   A lesson begins at 3:50 p.m. and lasts 50 minutes. When does it finish?

   Reveal explanation

   Answer: 4:40 p.m.

   Add 50 minutes to the start time, crossing each next hour carefully. 3:50 p.m. plus 50 minutes is 4:40 p.m..

4. A4

   How many minutes pass from 11:40 p.m. to 12:30 a.m.?

   Reveal explanation

   Answer: 50 min

   Count from 11:40 p.m. to the next whole hour, then onward to 12:30 a.m.. The intervals add to 50 minutes.

5. A5

   A student leaves at 2:40 p.m., walks 25 minutes, then studies 45 minutes. At what time does studying end?

   Reveal explanation

   Answer: 3:50 p.m.

   First reach 3:05 p.m. after walking, then add 45 minutes. Finish at 3:50 p.m..

6. A6

   Express 275 seconds in minutes and seconds.

   Reveal explanation

   Answer: 4 min 35 s

   Group the 275 seconds into complete 60-second minutes, then count the 35 remaining seconds.

7. A7

   How many minutes pass from 11:40 a.m. to 12:15 p.m.?

   Reveal explanation

   Answer: 35 min

   Count from 11:40 a.m. to the next whole hour, then onward to 12:15 p.m.. The intervals add to 35 minutes.

8. A8

   A lesson begins at 2:35 p.m. and lasts 35 minutes. When does it finish?

   Reveal explanation

   Answer: 3:10 p.m.

   Add 35 minutes to the start time, crossing each next hour carefully. 2:35 p.m. plus 35 minutes is 3:10 p.m..

9. A9

   How many minutes pass from 11:40 p.m. to 1:10 a.m.?

   Reveal explanation

   Answer: 90 min

   Count from 11:40 p.m. to the next whole hour, then onward to 1:10 a.m.. The intervals add to 90 minutes.

10. A10

    A student leaves at 10:35 a.m., walks 15 minutes, then studies 55 minutes. At what time does studying end?

    Reveal explanation

    Answer: 11:45 a.m.

    First reach 10:50 a.m. after walking, then add 55 minutes. Finish at 11:45 a.m..

11. A11

    Express 28 days in weeks and days.

    Reveal explanation

    Answer: 4 weeks 0 days

    One week is seven days. 28 = 7 × 4 + 0.

12. A12

    How many minutes pass from 2:05 p.m. to 4:20 p.m.?

    Reveal explanation

    Answer: 135 min

    Count from 2:05 p.m. to the next whole hour, then onward to 4:20 p.m.. The intervals add to 135 minutes.

13. A13

    A lesson begins at 11:05 a.m. and lasts 25 minutes. When does it finish?

    Reveal explanation

    Answer: 11:30 a.m.

    Add 25 minutes to the start time, crossing each next hour carefully. 11:05 a.m. plus 25 minutes is 11:30 a.m..

14. A14

    How many minutes pass from 11:35 a.m. to 12:40 p.m.?

    Reveal explanation

    Answer: 65 min

    Count from 11:35 a.m. to the next whole hour, then onward to 12:40 p.m.. The intervals add to 65 minutes.

15. A15

    A student leaves at 8:15 a.m., walks 25 minutes, then studies 55 minutes. At what time does studying end?

    Reveal explanation

    Answer: 9:35 a.m.

    First reach 8:40 a.m. after walking, then add 55 minutes. Finish at 9:35 a.m..

16. A16

    Convert 2 h 45 min into minutes.

    Reveal explanation

    Answer: 165 min

    Each hour is 60 minutes. 2 × 60 + 45 = 165 minutes.

17. A17

    A trip begins at 11:40 p.m. and lasts 40 minutes. On which day does it finish and at what time?

    Reveal explanation

    Answer: Next day at 12:20 a.m.

    20 minutes reach midnight; 20 minutes more reach 12:20 a.m. on the next day.

18. A18

    Why is 6 hours 15 minutes not 615 minutes?

    Reveal explanation

    Answer: 375 minutes

    Each hour has 60 minutes, so 6 hours 15 minutes is 360+15=375 minutes.