SOLUTION: A tourist can bicycle 28 miles in the same time as he can walk 8 miles. If he can ride 10 mph faster than he can walk, how much time (in hr) should he allow to walk a 25-mile trail

Let x be his walking speed, in miles per hour.


Then his speed bicycling is (x+10) mph.


The time equation says

     = .    (A tourist can bicycle 28 miles in the same time as he can walk 8 miles.)


To solve it, cross multiply

    28x = 8*(x+10).


Now simplify and solve for x

    28x = 8x + 80

    28x - 8x = 80

    20x      = 80

      x      = 80/20 = 4.


Thus his walking speed is 4 miles per hour.


Hence, he will spend  25/4 = 6 hours and 15 minutes on the 25-mile trail walking.