Kibet left school by bicycle at 8:00 a.m. and took 1 ½ hours to reach the market 20 km away. Akinyi left the school for the market by car at 8:30 a.m. The average speed of the car was 80 km /h. What was the difference between their arrival times?
Kibet rode from 8:00 to 9:30
Akinyi rode for 20/80 = 1/4 hr, so the car arrived at 8:45
Now figure the time difference.