Terrance and jesse are training for a long-distance race. terrace trains at a rate of 6 miles every half hour, so his unit rate is 12 miles per hour, and jesse trains at a rate of 2 miles every 15 minutes, so his unit rate is 8 miles per hour. sandra runs at the rate of 8 miles in 45 minutes. how does her unit rate compare to terrance's and to jesse?

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?