Suppose that 7 customers arrive, and each orders a different appetizer to share from a choice of 12 appetizers.

a in how many ways can this be done?
b. why is this answer the same as the number of ways that 5 customers can order different appetizers?

Apassenger train and a freight train leave san jose at 3pm, traveling in the same direction. the passenger train is going three times as fast as the freight train. at 6pm they are 240 miles apart. how fast is each travelling? explain your answer and show your