If a year only had 364 days then we could use the same calendar every year. but actually most years have 365 days, and a leap year has 366 days. for the relevant years, a leap year occurs when the year is divisible by 4
i was just about to throw my calendar away for 2013 when i wondered when i would first be able to reuse it. in which year would that be? justify your answer.

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?