Answer:
4 km/min
Step-by-step explanation:
Applying
S = (d₂-d₁)/(t₂-t₁).............. Equation 1
Where S = speed of the car, d₁ = Intial reading of the odometer, d₂ = Final reading of the odometer, t₁ = initial time, t₂ = final time.
From the question,
Given: d₁ = 68420 km, d₂ = 68540 km, t₁ = 9:00 am, t₂ = 9:30 am
Substitute these values into equation 1
S = (68540-68420)/(9:30-9:00)
S = 120/30
S = 4 km/min.