dave walked to his friend's house at a rate of 4 mph and returned back biking at a rate of 10 mph. if it took him 18 minutes longer to walk than to bike, what was the total distance of the round trip?

i need on it

What values of x satisfy the inequality x^2-9x< 0? how is your answer shown on the graph?

Julie goes to the sports store and spends $40.50 before tax. she buys a pair of shorts for $21.75 and 3 pairs of socks that each cost the same amount. how much does each pair of socks cost? $$

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?