I have two problems and need to know the formula and calculations.
1-1. A group holds a raffle to raise money. They sell 100 raffle tickets for $5 each. There is one grand prize worth $100, three second place prizes worth $25 each and five 3rd place prizes worth $10 each. Find the expected value associated with the purchase of one ticket. (Remember to subtract the cost of playing from your winnings)
2-The Mathematics Department at Sun Tan University is sending a delegation of mathematicians and graduate students to a conference. They will pay for 4 mathematicians and 5 graduate students to go. If the department has 16 mathematicians and 24 graduate students, how many different delegations are possible?