Atruck weighs 17,000 lbs when it's trailer is empty, it gets 8 miles per gallon. it picks up 7.5 metric tons and travels 57 miles on flat ground and 20 miles at an 2.5% incline. the trucks mpg efficiency is reduced by 2.5, of the original mpg with no cargo, for every 1% incline that the truck travels. the first 9 metric tons of cargo reduces the mpg efficiency by 0.25%. what were the miles per gallon achieved by the truck?

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?