SOLUTION
From the question, we are given that the distance between Station A and B = 220 feet
The track rise is 6 feet
We need to find the slope of the railway track between station A and B
The maximum grade allowed between two stations in a rapid-transit system is 3.6%
We know that the slope of the railway track is equal to the gradient of the tracks.
So, the slope of the railway track is defined as the ratio of the distance between the stations and track rises.
Which is

So, x = 2.73%
Hence the grade of the tracks between these stations is 2.73%
This is less than the maximum grade 3.6% allowed between two stations in a rapid-transit rail system.
Hence this meets the rapid-transit rail standards