Question 1172905
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<pre>

Car A spends  {{{10/100}}} = {{{1/10}}} of an hour = 6  minute to get the finish.


Hence, car B must reach the finish in 5 minutes  (5 = 6 - 1).


It means that car B must move at the speed of  {{{10/5}}} = 2 kilometers per minute, or 120 km/h.    <U>ANSWER</U>
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Solved (mentally).