Answer: he hiked 5.6 miles up the canyon.
Explanation:
Let x represent his speed hiking uphill.
His speed running downhill was 2.8 mph greater than his speed hiking uphill. This means that his speed running downhill would be x + 2.8
Distance = speed × time
Kevin hiked up Lamb’s Canyon in 2 hours. This means that the distance covered by hiking uphill is 2 × x = 2x
He ran back downhill in 1 hour. This means that the distance covered by running downhill is 1 × (x + 2.8) =
x + 2.8
Since the distance uphill is the same as the distance downhill, then
2x = x + 2.8
2x - x = 2.8
x = 2.8
Therefore, the distance hiked up the canyon is
2x = 2 × 2.8 = 5.6 miles