5. At a party, each person shakes hands once with every other person at the party. How many handshakes will happen if there are: a) 4 people at the party? b) 5 people at the party? c) 11 people at the party? 6. The dimensions of poster board paper at a store are 55 cm by 70 cm, and it sells at $5.49. A second poster board paper measures 27.5 cm by 35 cm. Given the price of the first poster board paper, what would be an appropriate price for the second poster board paper? Give reasons for your answer.