In a school, the ratio of students of class 9 to that of class 10 is 3:2. 30% of the students of class 9 and 10%of the students of class 10 were elected to the school student committee. What fraction of the total number of students of the two classes was selected to the school student committee?

The management of a supermarket wants to adopt a new promotional policy of giving a free gift to every customer who spends more than a certain amount per visit at this supermarket. the expectation of the management is that after this promotional policy is advertised, the expenditures for all customers at this supermarket will be normally distributed with a mean of $95 and a standard deviation of $20. if the management wants to give free gifts to at most 10% of the customers, what should the amount be above which a customer would receive a free gift?