a. A lottery ticket has one $1,000 winning ticket, one $500 ticket and five $100 tickets. One thousand tickets are sold at $3 per ticket. Find the expectation of a person buys one ticket.
b. If a player rolls two dice and gets a sum of 2 or 12, she wins $20. If she rolls a 7, she wins $5. the cost to play the game is $3. Find the expectation on a single play.