Dave and Ranjit took part in a race. Both boys started running at the same time. After 40 min, Ranjit had completed the race but Dave had another 800 m to complete the race. Ranjit ran at an average speed of 80 m/min. What was Dave's average speed?

1. Calculate the total distance of the race using Ranjit's speed and time.

Total distance $= 80 \text{ m/min} \times 40 \text{ min} = 3200 \text{ m}$

2. Calculate the distance Dave ran in 40 minutes.

Distance Dave ran $= 3200 \text{ m} - 800 \text{ m} = 2400 \text{ m}$

3. Calculate Dave's average speed.

Dave's average speed $= \frac{2400 \text{ m}}{40 \text{ min}} = 60 \text{ m/min}$