I need help with this

Problem 5 (10 points) Two independent experiments are run in which two different types of paint are compared. Eighteen specimens are painted using type A and the drying time in hours is recorded on each. The same is done with type B. The population standard deviation are both known to be 1.0, assume that the mean drying time is is equal for two types of paint. Find P(XA XB > 1). Does this seem to be a reasonable result if the two population mean drying times truly are equal