Page 240 - Services Selection Board (SSB) Interviews

236 Clocks
And angle moved by minute is 6Q (From the 12:00 position) hence angle between them is
6Q – (60P + Q)/2 = 11/2Q – 30P
Angle between two hands at P hours Q Minute is given by 11Q − 30P
2
Example: Find the angle between minute hand and hour hand at 4:40PM
Solution: From the formula angle between these two hands is 11 × 40/2 – 30 × 4 = 220 – 120 = 100°
Example: Find the angle between minute hand and hour hand at 4:15 PM

Solution: From the formula angle between these two hands is 11 × 15/2 – 30 × 4 = 82.5 – 120 = – 37.5° ignoring
o
the negative sign the required angle is 37.5 .

1. ConCept AppliCAtor

1. Find the angle between minute hand and hour hand 6. At what time between 3PM to 4PM minute hand and
at 6:30 AM hour hand will coincide?
4
(a) 25° (b) 22.5° (a) 3:16 11 (b) 3: 15 11
4
(c) 15° (d) None of these (c) 3:17 4 (d) None of these
11
2. Find the angle between minute hand and hour hand 7. At what time between 3PM to 4PM minute hand and
at 11:50 AM hour hand will be opposite to each other?
(a) 55° (b) 22.5° (a) 3:47 1 (b) 3: 48 1
(c) 15° (d) None of these 11 11
1
(c) 3:49 11 (d) None of these
3. Find the angle between minute hand and hour hand 8. At what time between 4PM to 5PM minute hand and
at 4:20 AM hour hand will be at right angle to each other?
(a) 10° (b) 12.5° (a) 4:7 5 (b) 4: 4 5
(c) 15° (d) None of these 11 11
5
(c) 4:9 11 (d) None of these
4. Find the angle between minute hand and hour hand 9. At what time between 9PM to 10PM minute hand
at 1:40 AM and hour hand will coincide?
(a) 180° (b) 190° (a) 9:49 1 (b) 9: 48 1
(c) 175° (d) None of these 11 11
1
(c) 9:44 11 (d) None of these
5. Find the angle between minute hand and hour hand 10. At what time between 9PM to 10PM minute hand
at 10:10 AM and hour hand will be opposite to each other?
(a) 245° (b) 195° 4 4
(c) 175° (d) None of these (a) 9:15 11 (b) 9: 16 11
4
(c) 9:12 11 (d) None of these

2. ConCept Builder

1. At what time between 2PM and 3PM the angle (a) 37° (b) 33°
o
between minute hand and hour hand is 100 . (c) 39° (d) None of these
6
6
(a) 2:14 11 (b) 2:12 11 3. Find the percentage change in angle between minute
6
(c) 2:18 11 (d) None of these hand and hour hand from 2PM to 6PM.
2. Find the angle between minute hand and hour hand (a) 100 (b) 200
at 2:18 AM (c) 250 (d) None of these