At 7 o’ clock, the hour hand is at 210 degrees from the vertical.
In 20 minutes,
Hour hand = 210 + 20 x (0.5) = 220 (The hour hand moves at 0.5 dpm)
Minute hand = 20 x (6) = 120 (The minute hand moves at 6 dpm)
Difference or angle between the hands = 220 - 120 = 100 degree