How many different 2-letter passwords can be formed from the letters O, P, Q, R, S, T, and U if no repetition of letters is allowed? The problem involves a__
because the__
of letters selected
___matter

How do i do this activity, is appreciated

Can someone me with this problem i don't understand i need

Sophia wrote an equation to represent the revenue of a movie theater for one day. she let x represent the number of child tickets sold and y represents the nunver of adult tickets sold. if a child ticket cost $4, an adult ticket cost $6, and the total revenue for the daybwas $420, which equation could sophia use to represent the number of chikd and adult tickets that were sold?