The definition at the bottom of the graph says: The total downhill (or downward is the same thing, actually) is the same of the distance given in the first graph and that in the second graph.
Now, for a skier at 20 mph during his reaction time is 15 (from the first graph) and at 20 mph is 50 (in the second graph. So, the total is 65 feet.
The same you have to sum for the second skier which is a total distance of 285.
Now, the difference in % of the two distances is \(\frac{65}{285}\) \(\approx 0.23\)
But the question ask for
approximately what percent smaller than.
So this means that on a total distance of 100 you have to subtract 0.23 which is 77%.
D is the answer.
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