192 | 1 | ° |
2 |
197 | 1 | ° |
2 |
197 | 1 | ° |
2 |
Angle traced by hour hand in | 125 | hrs = | ❨ | 360 | x | 125 | ❩ | ° | = 312 | 1 | ° | . |
12 | 12 | 12 | 2 |
Angle traced by minute hand in 25 min = | ❨ | 360 | x 25 | ❩ | ° | = 150°. |
60 |
∴ Reflex angle = 360° - | ❨ | 312 | 1 | - 150 | ❩ | ° | = 360° - 162 | 1 | ° | = 197 | 1° | . |
2 | 2 | 2 |
43 | 5 | min. past 5 |
11 |
43 | 7 | min. past 5 |
11 |
43 | 7 | min. past 5 |
11 |
To be at right angles and that too between 5.30 and 6, the minute hand has to gain (25 + 15) = 40 min. spaces.
55 min. spaces are gained in 60 min.
40 min. spaces are gained in | ❨ | 60 | x 40 | ❩min | = | 43 | 7 | min. |
55 | 11 |
∴ Required time = 43 | 7 | min. past 5. |
11 |
Angle traced by the hour hand in 6 hours = | ❨ | 360 | x 6 | ❩ | ° | = 180°. |
12 |
∴ The watch gains | ❨ | 2 + 4 | 4 | ❩min. | or | 34 | min. in 170 hrs. |
5 | 5 |
Now, | 34 | min. are gained in 170 hrs. |
5 |
∴ 2 min. are gained in | ❨ | 170 x | 5 | x 2 | ❩hrs | = 50 hrs. |
34 |
∴ Watch is correct 2 days 2 hrs. after 12 p.m. on Monday i.e., it will be correct at 2 p.m. on Wednesday.
AM
12:00
1:05
2:11
3:16
4:22
5:27
6:33
7:38
8:44
9:49
10:55
PM
12:00
1:05
2:11
3:16
4:22
5:27
6:33
7:38
8:44
9:49
10:55
The hands overlap about every 65 minutes, not every 60 minutes.
∴ The hands coincide 22 times in a day.
Angle traced by hour hand in | 17 | hrs = | ❨ | 360 | x | 17 | ❩ | ° | = 255°. |
2 | 12 | 2 |
Angle traced by min. hand in 30 min. = | ❨ | 360 | x 30 | ❩ | ° | = 180°. |
60 |
∴ Required angle = (255 - 180)° = 75°.
Angle traced by hour hand in 5 hrs 10 min. i.e., | 31 | hrs = | ❨ | 360 | x | 31 | ❩ | ° | = 155°. |
6 | 12 | 6 |
Angle traced by it in | 11 | hrs = | ❨ | 360 | x | 11 | ❩ | ° | = 110°. |
3 | 12 | 3 |
Angle traced by minute hand in 60 min. = 360°.
Angle traced by it in 40 min. = | ❨ | 360 | x 40 | ❩ | ° | = 240°. |
60 |
∴ Required angle (240 - 110)° = 130°.
49 | 1 | min. past 9 |
11 |
48 | 2 | min. past 9 |
11 |
49 | 1 | min. past 9 |
11 |
55 min. spaces gained in 60 min.
45 min. spaces are gained in | ❨ | 60 | x 45 | ❩min or 49 | 1 | min. |
55 | 11 |
∴ The hands are together at 49 | 1 | min. past 9. |
11 |
32 | 8 | min. |
11 |
36 | 5 | min. |
11 |
32 | 8 | min. |
11 |
60 min. spaces are covered in | ❨ | 60 | x 60 | ❩min. | = 65 | 5 | min. |
55 | 11 |
Loss in 64 min. = | ❨ | 65 | 5 | - 64 | ❩ | = | 16 | min. |
11 | 11 |
Loss in 24 hrs = | ❨ | 16 | x | 1 | x 24 x 60 | ❩min. | = | 32 | 8 | min. |
11 | 64 | 11 |
So, in a day, the hands point in the opposite directions 22 times.
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