7. A cultural society is arranging a party for its members. The cost of a band to play music, the amount that the caterer will charge, the rent of a hall to give the party, and other expenses (in dollars) are uniform random variables over the intervals (1300, 1800), (1800, 2000), (800, 1200), and (400, 700), respectively. If the number of party guests is a random integer from (150, 200], what is the least amount that the society should charge each participant to have no loss, on average?