Pat and Kelly went hiking in the mountains. They started at 9,100 ft. They climbed 1,200 ft the first day, descended 900 ft the second day, and climbed 1,000 ft the third day. On the fourth day they descended 800 ft. What was the average altitude at which they hiked?
9,100 + 1,200 + 1,000 - 900 - 800 = ?
Divide the answer by 4.
To find the average altitude at which Pat and Kelly hiked, we need to calculate the total change in altitude and divide it by the number of days.
First, let's calculate the total change in altitude. On the first day, they climbed 1,200 ft, on the second day they descended 900 ft, on the third day they climbed 1,000 ft, and on the fourth day they descended 800 ft.
Total change in altitude = (1,200 ft) + (-900 ft) + (1,000 ft) + (-800 ft)
= 1,200 ft - 900 ft + 1,000 ft - 800 ft
= 500 ft
Now, we need to calculate the average altitude. Since they started at 9,100 ft, we need to add the total change in altitude to the starting altitude and divide it by the total number of days.
Average altitude = (Starting altitude + Total change in altitude) / Number of days
Starting altitude = 9,100 ft
Total change in altitude = 500 ft
Number of days = 4
Average altitude = (9,100 ft + 500 ft) / 4
= 9,600 ft / 4
= 2,400 ft
Therefore, the average altitude at which Pat and Kelly hiked was 2,400 ft.