To estimate the difference between the mean time that it takes to drive between two branches of his company using two different routes, Jim keeps a record of the times that he took to drive between the branches using these two routes and the summary statistics are shown below # of trips Mean time Standard Deviation Route A 93 minutes 15 minutes Route B 81 minutes 21 minutes If treat the trips as simple random samples, construct a 99% confidence interval for the difference between the means of the route A and the route B ( mean route A - mean route B) and write the upper end point of the interval. Round you answer to three digits after the decimal sign