The time t (in hours) that it takes a pump to empty a tank of water varies inversly with the pumping rate r (in gallons per hour). Find the constant of variation if it takes 3 hours to empty a tank of water when the pumping rate is 80 gallons per hour.

Given a normal distribution with µ =50 and σ =4, what is the probability that 5% of the values are less than what x values? between what two x values (symmetrically distributed around the mean) are 95 % of the values? instructions: show all your work as to how you have reached your answer. don’t simply state the results. show graphs where necessary.