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OG16. P213
84.At a certain instant in time, the number of cars, N, traveling on a portion of a certain highway can be estimated by the formula
N=200Ld/(600+s²)
where L is the number of lanes in the same direction, d is the length of the portion of the highway, in feet, and s is the average speed of the cars, in miles per hour. Based on the formula, what is the estimated number of cars traveling on a 1/2 mile portion of the highway if the highway has 2 lanes in the same direction and the average speed of the cars is 40 miles per hour? (5,280 feet = 1 mile)
A.155
B.98
C.80
D.48
E.24
看了OG的解释,仍然搞不懂,为什么不把mile和feet化为同一个单位?就是直接把所有数值带进去吗?求大神解释!!!!
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