What is the answer to this question?

Country carpets charges $22 per square yard for carpeting, and an additional installation fee of $100. city carpets charges $25 per square yard for the same carpeting, and an additional installation fee of $70

(hurry! ) which expression is equivalent to the following complex fraction?

Ascientist wants to use a model to present the results of his detailed scientific investigation. why would a model be useful? a )because the model makes the concepts easier to understand b) because the model is easy to put together and to use c) because the model prevents other scientists from asking questions d) because the model requires the audience to pay full attention to it i don't know what to choose because between a and d a is much more likely than d because it only wants to get the attention of the audience. i'm confuse.