John and Susan hiked up an 18-mile mountain trail at 5mph. They hiked down at 4mph. How long did the hike take?
Up time = 18 miles/5 mph
Down time = 18 miles/4 mph
Compute and add the two times.
Most people go up mountains slower than they come down. They must be unusual climbers.
To calculate the time it took for John and Susan to hike up the mountain trail and down, we need to calculate the time for each direction separately and then add them together.
Let's start with the time it took for them to hike up the mountain trail:
Distance = 18 miles
Speed = 5 mph
To calculate the time, we can use the formula: time = distance / speed
Time to hike up = 18 miles / 5 mph = 3.6 hours
Now let's calculate the time it took for them to hike down the mountain trail:
Distance = 18 miles
Speed = 4 mph
Time to hike down = 18 miles / 4 mph = 4.5 hours
Finally, we add the time it took to hike up and the time it took to hike down:
Total hiking time = 3.6 hours + 4.5 hours = 8.1 hours
So, it took John and Susan 8.1 hours to complete the hike.