Bus and Subway Trips in a City

In a small city, two types of public transport, bus and subway, are used by commuters. The total number of trips made by buses and subways is represented by the equation:

$$x + y = 200$$

where $x$ is the number of bus trips and $y$ is the number of subway trips. In addition, for every bus trip, there are 3 subway trips, given by the equation:

$$y = 3x$$

What is the total number of bus trips and subway trips made if both conditions are met?