Alice enjoys visiting Karen at her house. To be able to get to Karen's house from her house, she needs to travel uphill and then traverse across ground level. Alice takes 10 hours to perform the round trip. She moves at 4km per hour on level ground, 12km per hour downhill and 2.4 or 12/5km per hour uphill. How far is Alice's house from Karen's house?

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.