Correct Answer - Option 2 : 100
°
Angle traced by hour hand in 12 hrs. = 360°
Angle traced by hour hand in 1 hour = 360°/12 = 30°
At 7:20 angle traced by hour hand = (7 + 20/60) × 30° = (22/3) × 30° = 220°
Angle traced by the minute hand in 1 minute = 360°/60 = 6°
In 20 minutes, angle traced by minute hand = 20 x 6° = 120°
The angle between the minute and hour hand is 220° – 120° = 100°
Hence, 100° is the correct answer.
TRICK:
Angle between hands = |30 × H – (11/2) × M|
where H = 7 and M = 20
Angle between hands = |30 × 7 - (11/2) × 20|
= |210 – 110|
= |100|
= 100°
