A group of 7 campers has 4 hours to hike to a lighthouse and back before sundown. the lighthouse is 28 meters high. it is located 12 kilometers from camp. how fast do they have to walk?

We must take note that the 28 meters high is simply a diversion. What we only need is the 4 hours and 12 kilometers distance. The formula for calculating the speed or velocity is:

velocity = distance / time

Therefore:

velocity = 12 km / 4 h

velocity = 3 km / h = 0.83 m / s