the management of a supermarket wants to adopt a new promotional policy of giving a free ice cream to every customer who spends more than a certain amount per visit at this supermarket. the expectation of managent 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.$ a$)$ if management wants to give free ice cream to at most $10\%$of its customers $,$ what should the amount be above which a customer would recieve the free ice cream. b$)$ if management wants to give free ice cream to at most $25\%$ of its customers what should the amount be above which a customer would recieve the free ice cream $?$