How to find the accurate estimate of the volume?

The length of each stair is 11 inches. what is the rise, r, for each stair? round to the nearest inch. 2 inches 7 inches 17 inches 24 inches

Acar travels at an average speed of 56 miles per hour. how long does it take to travel 196 miles

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?