The distance from City A to City B is 180 miles. While driving from City A to City B, Cara drives at a constant speed of 30 miles per hour. Dan leaves City A 120 minutes after Cara. What is the minimum constant speed in miles per hour that Dan must exceed in order to arrive in City B before Cara?  Choose the correct choice from the following answers
A) 42	B) 45	C) 46	D) 48	E) 50
The time it takes Cara to drive to City B is 180 / 30= 
<gadget id="calculator">180 / 30</gadget>
<output>6</output>
6 hours.   Dan needs to take less than 4 hours for the trip.   Dan needs to exceed a constant speed of  180 / 4= 
<gadget id="calculator"> 180 / 4</gadget>
<output>45</output>
45 miles per hour.   The answer is 45.
<result>B</result>
The distance from City A to City B is 180 miles. While driving from City A to City B, Cara drives at a constant speed of 30 miles per hour. Dan leaves City A 120 minutes after Cara. What is the minimum constant speed in miles per hour that Dan must exceed in order to arrive in City B before Cara?