MathDB

One afternoon Elizabeth noticed that twice as many cars on the expressway carried only a driver as compared to the number of cars that carried a driver and one passenger. She also noted that twice as many cars carried a driver and one passenger as those that carried a driver and two passengers. Only 10% of the cars carried a driver and three passengers, and no car carried more than four people. Any car containing at least three people was allowed to use the fast lane. Elizabeth calculated that

\frac{m}{n}

of the people in cars on the expressway were allowed to ride in the fast lane, where

m

and

n

are relatively prime positive integers. Find

m + n

13

Problems(2)