Question

On a highway a wreck occurred and caused an 8 mile traffic jam on one side of the road. The average car is 14.5 feet in length, the average truck is 21 feet in length, and the average 18 wheeler tractor trailer is 73 feet in length. 70% of the traffic jam consists of cars, 20% trucks, and 10% 18 wheeler tractor trailers. If the average distance between vehicles is 4 feet, how many vehicles are stuck in the traffic jam?

Answer 1

1647

Explanation:

Given the following information:

Length of traffic = 8 miles

Average Length of vehicles on the road :

Cars = 14.5 feets

Trucks = 21 feets

18 Wheeler tractor = 73 Feets

% distribution of the different vehicles :

Cars = 70% = 0.7

Trucks = 20% = 0.2

18 wheeler tractor = 10% = 0.1

Distance between vehicles = 4feets

Number of vehicles stuck in the traffic :

Let number of vehicles = v

Summation of (number of vehicles * length of each vehicle) + distance between each vehicle = Length of traffic

Total distance between each vehicle = 4(v-1)

(0.7v * 14.5) + (0.2v * 21) + (0.1v * 73) + 4(v - 1) = 8 miles

1 mile = 5280

8 miles = (5280 * 8) = 42,240

10.15v + 4.2v + 7.3v + 4v - 4 = 42240

25.65v = 42240 + 4

25.65v = 42244

v =42244 / 25.65

v = 1646.939

v = 1647.