List a pair of supplementary angles and a pair of vertical angles

The hawaiian alphabet has 12 letters. how many permutations are posible for each number of letters?

Oscar and julie ashton are celebrating their 15th anniversary by having a reception hall. they have budgeted $4,500 for their reception. if the reception hall charges a $90 cleanup fee plus & 36 per person, find the greatest number of people that they may invite and still stay within their budget.

I’m stuck on this equation, anyone got the answer?