The distance from City A to City B is 240 miles. While driving from City A to City B, Jim drives at a constant speed of 40 miles per hour. Kerri leaves City A 60 minutes after Jim. What is the minimum constant speed in miles per hour that Kerri must exceed in order to arrive in City B before Jim?  Choose the correct option.
A) 42
B) 44
C) 46
D) 48
E) 50
The time it takes Jim to drive to City B is 240 / 40= 
<gadget id="calculator">240 / 40</gadget>
<output>6</output>
6 hours.   Hannah needs to take less than 5 hours for the trip.   Hannah needs to exceed a constant speed of  240 / 5= 
<gadget id="calculator"> 240 / 5</gadget>
<output>48</output>
48 miles per hour.   The answer is 48.
<result>D</result>
The distance from City A to City B is 240 miles. While driving from City A to City B, Jim drives at a constant speed of 40 miles per hour. Kerri leaves City A 60 minutes after Jim. What is the minimum constant speed in miles per hour that Kerri must exceed in order to arrive in City B before Jim?