In how many ways can a state select a governor and lieutenant governor from a pool of 11 candidates

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.

Julia bought 7 hats a week later half of all her hats were destroyed in a fire. there are now only 12 hats left with how many did she start

Jenny made a scale drawing of a city. the scale she used was 5 inches = 1 yard. what is the scale factor of the drawing?