Ashley and Bill simultaneously begin traveling around a circular road. Both start from the same point. Ashley travels counterclockwise and Bill travels clockwise. The two first meet after Ashley travels 40 miles per hour for 2.5 hours and Bill travels 6.4 miles per hour for 4 hours. What is the approximate diameter of the circular road (in miles)? Use 3.14 for ?.
A. 20
B. 40
C. 46.4
D. 116
E. 125.6
Answer
To visualize this question, a circle is just a line segment joined at its two ends. Lets first cut the circle at a the starting point and make it in to a straight line.
Notice that cars A and B are at opposite ends of the line traveling towards each other. After 2.5 hours, and at a rate of 40 mph, Car A has traveled 100 miles east. Car B has traveled 4 hours at 6.4 miles: 25.6 miles.
To determine the diameter we simply plug in to the formula C = ? D where D is the diameter and C is the circumference and ? is about 3.14. We can take C to equal 126 and ? to equal 3.14. The diameter is therefore equal to: D = C/?= 126/3.14 equals approximately 40.
Correct Answer - Choice B