At a certain instant in time, the number of cars, N,

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Source: Official Guide

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

\(N = \frac{200Ld}{600+s^2}\)

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. 96
C. 80
D. 48
E. 24

The OA is D
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by Jay@ManhattanReview » Mon Nov 25, 2019 11:10 pm
BTGmoderatorLU wrote:Source: Official Guide

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

\(N = \frac{200Ld}{600+s^2}\)

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. 96
C. 80
D. 48
E. 24

The OA is D
So, we have L = 2, d = 1/2 miles = 5,280/2 = 2,540 feet, and s = 40

Thus, \(N = \frac{200Ld}{600+s^2} = \frac{200*2*2540}{600+40^2} = 48\)

The correct answer: D

Hope this helps!

-Jay
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