40×9=360 km
It's 360 kilometers from Port A to Port B.
360 degrees (40+20)=6 hours
It takes six hours to return to port a.
2. Liu Min learns to draw by riding a bicycle in the Kadao Children's Palace. She drove at a speed of 240 meters per minute 15 minutes to the Children's Palace, and found that she didn't bring her drawing pen, so she hurried home, shortening it by 3 minutes. How many meters does she walk home every minute?
240×15 ÷ (15-3) = 300m.
Walk 300 meters home every minute.