The sum of half of a number x, and another number y is 54. X is 18 more than y. Find x and y

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.

Jim had 15 minutes to do 5 laps around his school what would his time be

If a runner who runs at a constant speed of p miles per hour runs a mile in exactly p minutes what is the integer closest to the value p