HELP ME PLEASE

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.

Cody was 165cm tall on the first day of school this year, which was 10% taller than he was on the first day of school last year.

Rick is driving to his uncles house in greenville,which is 120 miles from ricks town .after covering x miles rick she's a sign stating that greensville is 20 miles away. which equation when solved will give the value of x. a: x+120 = 20 b: x x120 =20 c: x +20 equals 120 d: x x20= 120