The angle between hour hand and minute hand is .
The hour hand of a clock is at 9 and the minute hand makes an angle of 90∘ with the hour hand. If the minute hand is ahead of the hour hand, what time is it now?
I left home for bringing milk between 7am and 8am. The angle between the hour-hand and the minute hand was 90∘. I returned home between 7 am and 8 am. Then also the angle between the minute-hand and hour-hand was 90∘. At what time (nearest to second) did I leave and return home?