At the beginning of the week, naveen has 87 trading cards. On monday, he gets 9 more. On tuesday, he gives 16 away. On wednesday, he is given 3 by a friend. On thursday, he sells all of his cards to a collector. The collector pays him a rate of c for every card that naveen has. If naveen earns $124. 50 from the sale, what is c, the rate that the collector pays for each card?.