Determine what they are trying to ask, and what you will need to solve it
Eliminate any non-essential information
Draw a picture, graph, or equation
In moments of high stress like exam taking, always work with the paper they give you to avoid careless mistakes.
Solve.
This question is poorly worded and can be confusing at first. The trick to understanding this question is that you must realise that it only wants the number of houses on one side of the street. To realize this, you will notice that if we took the sum of both sides here, you would have way more than the highest possible answer choice, therefore it must be lower.
The best way to solve this problem is to use a drawing. The parameters for this can be found in the sample image given to us in this problem. One side is increasing and the other is decreasing.