MathDB
Passing Cars

Source:

February 12, 2009

Problem Statement

In order to pass B B going 40 40 mph on a two-lane highway, A A, going 50 50 mph, must gain 30 30 feet. Meantime, C C, 210 210 feet from A A, is headed toward him at 50 50 mph. If B B and C C maintain their speeds, then, in order to pass safely, A A must increase his speed by: <spanclass=′latex−bold′>(A)</span> 30 mph<spanclass=′latex−bold′>(B)</span> 10 mph<spanclass=′latex−bold′>(C)</span> 5 mph<spanclass=′latex−bold′>(D)</span> 15 mph<spanclass=′latex−bold′>(E)</span> 3 mph <span class='latex-bold'>(A)</span>\ \text{30 mph} \qquad <span class='latex-bold'>(B)</span>\ \text{10 mph} \qquad <span class='latex-bold'>(C)</span>\ \text{5 mph} \qquad <span class='latex-bold'>(D)</span>\ \text{15 mph} \qquad <span class='latex-bold'>(E)</span>\ \text{3 mph}
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