Busy Intersection

Question

An engineer is studying a busy intersection. In 1 hour, the number of cars going north-south was 3/4 of those going east-west, and the total number of cars was 1400. Find the number of cars going north-south and east-west.

Answer 1

Let e = # cars going East/West

Let n = # cars going North/South

 

n = (3/4)e

n + e = 1400

 

Substitute (3/4)e in place of n in 2nd equation and solve for e

 

(3/4)e + e = 1400

(7/4)e = 1400

e = 1400(4/7) = 800

 

800 cars went East/West

600 cars went North/South