A bike's distance-time graph for $4$ hours is: from $0\to 2$ h, distance increases from $0$ to $80$ km; from…

A bike's distance-time graph for $4$ hours is: from $0\to 2$ h, distance increases from $0$ to $80$ km; from $2\to 4$ h it increases from $80$ to $200$ km. In which interval is the bike faster?
  1. $0$ to $2$ h
  2. $2$ to $4$ h
  3. Both are equal
  4. Cannot be determined

Solution

Speed in first interval $= 80/2 = 40$ km/h; in second interval $= (200-80)/2 = 60$ km/h. So the bike is faster in $2\to 4$ h.

Asked in: IMO

Practice more INTRODUCTION TO GRAPHS questions on Aicharya