The scout troop hikes 7 km in 2 hr. At this pace, how far will the troop hike in 4 hr?

9 km

14 km

16 km

20 km

If the troops hike 7km/2hr (read 7 kilometers per 2 hours), then to find how far they'd hike 4hr, just find multiply the top and bottom by 2. We do this because we found that to get from 2 to 4, we multiply by 2. And since this is a rate, we multiply the top by this value as well, so 7x2=14km

14 kilometers because 4=2*2 and they walk 7 kilogram in 2 hours. 7*2=14. So the troop walked 14 kilometers in 4 hours.