Ella and Frank race around a running track. Ella runs at a constant rate of one lap every 3 minutes and Frank runs at a constant rate of one lap every 5 minutes. If they both start at the same time, how many minutes will it take for Ella to get exactly one lap ahead of Frank?	Choose one: A) 5.5 B) 6.5 C) 7.5 D) 8.5 E) 9.5
Let x be the number of minutes it takes for Ella to get one lap ahead.   Then Ella ran x/3 laps and Frank ran x/5 laps.   x/3 = 1+x/5   5x=15+3x   2x=15   x=7.5   The answer is 7.5.
<result>C</result>
Ella and Frank race around a running track. Ella runs at a constant rate of one lap every 3 minutes and Frank runs at a constant rate of one lap every 5 minutes. If they both start at the same time, how many minutes will it take for Ella to get exactly one lap ahead of Frank?