Points A and B on a map are 15 km apart if you follow the path. A troop of boy scouts leaves point A at 11:00 a.m. They are all carrying packs and travel 4 km/h until they reach point C at 12:25. From point C, if they want to reach point B by 14:00, how fast will they have to go?

Answer 1

The scouts took 1 hour and 25 minutes to travel from point A to point C, which is 1 hour and 25/60 = 5/4 hour.
So, they were able to travel 4 km/h x 5/4 hour = <<4*5/4=5>>5 km.
Point C is 15 km - 5 km = <<15-5=10>>10 km away from point B.
Thus, they have 14:00 - 12:25 = 1 hour and 35 minutes to travel from point C to point B, which is 1 hour and 35/60 = 19/12 hour.
Therefore, they need to travel 10km ÷ 19/12 hour = <<10/(19/12)=7.89>>7.89 km/h. Answer: \boxed{7.89}.