A car traveling at a certain constant speed takes 5 seconds longer to travel 1 km than it would take to travel 1 km at 60 km/hour. At what speed, in km/hr, is the car traveling?  Choices:
A) 70
B) 72
C) 74
D) 75
E) 55
Time to cover 1 kilometer at 80 kilometers per hour is 1/60 hours = 3,600/60 seconds = 60 seconds;   Time to cover 1 kilometer at regular speed is  60 + 5= 
<gadget id="calculator"> 60 + 5</gadget>
<output>65</output>
65 seconds= 65/3,600 hours = 1/55 hours;   So, we get that to cover 1 kilometer 1/55 hours is needed --&gt; regular speed 55 kilometers per hour (rate is a reciprocal of time or rate=distance/time).   Answer: 55
<result>E</result>
A car traveling at a certain constant speed takes 5 seconds longer to travel 1 km than it would take to travel 1 km at 60 km/hour. At what speed, in km/hr, is the car traveling?