Question

Two groups went hiking, leaving at the same time and arriving back at the same time. While one group moved away at the speed 6 mph and then moved back at the speed 4 mph, the other group moved all the way with the same speed. What was the speed of this second group, if both groups covered the same total distance, 24 miles?

Answer 1

Explanation:

d = the distance in one direction.

the time t1 it took group 1 was

t1 = d/6 + d/4

and t2 for group 2 moving with speed2 all the way

t2 = (d+d)/speed2

we know

2d = 24 miles

d = 12 miles

t1 = t2

so,

12/6 + 12/4 = 24/speed2

2 + 3 = 24/speed2

5 = 24/ speed2

5×speed2 = 24

speed2 = 24/5 = 4.8 mph

the second group moved with 4.8 mph.