Algebra
posted by Ellen P on .
How would you set up problem: your average rate traveling uphill was 2.2 kilometers per hour and average rate downhill was 3.3 kilometers per hour. If he spent a total of 12 hours hiking, how long was the trail?

length of trail  x km
time to go uphill = x/2.2
time to go downhill = x/3.3
x/2.2 + x/3.3 = 12
times 6.6
3x + 2x = 79.2
5x = 79.x = 15.84 km
the trail was 15.84 km long
check:
time uphill = 15.84/2.2 = 7.2 hrs
time downhill = 15.84/3.3 = 4.8 hrs
7.2 hrs + 4.8 hrs = 12 hrs
All is good!