Answer: on the first day, they hiked 9 miles.
On the second day, they hiked 16 miles.
Step-by-step explanation:
Let x represent the distance that the two hikers hiked from the first mountain to the second mountain.
Let y represent the distance that the two hikers hiked from the second mountain to the hollow.
The total distance is 25mi. This means that
x + y = 25 - - - - - - - - - - - - - -1
If the distance between the second mountain and the hollow is 7mi more than the distance from the first mountain to the second mountain, it means that
y = x + 7
Substituting y = x + 7 into equation 1, it becomes
x + x + 7 = 25
2x = 25 - 7
2x = 18
x = 18/2 = 9
y = x + 7 = 9 + 7
y = 16
