The hour hand goes 30 degrees per hour and 0.5 degrees per minute.

The minute hand walks 60 degrees per hour and 6 degrees per minute.

Calculation of departure time:

At 6 o'clock, there is 180 degrees per minute, which is 5.5 degrees less. Go out time 70/5.5 =140/11minute (6 o'clock).

Return time calculation

7 o'clock is 150 degrees, and every morning 1 minute is 5.5 degrees, so it is 40/5.5=80/ 1 1 minute earlier (relative to 7 o'clock).

So it took 60-220/ 1 1=40 minutes to go out.