What capacity must the tank in Prob. 15 have in

What capacity must the tank in Prob. 15 have in order that the probability that the tank will be emptied in a given week be 5%?

Data from Prob. 15

A small filling station is supplied with gasoline every Saturday afternoon. Assume that its volume X of sales in ten thousands of gallons has the probability density f(x) = 6x(1 - x) if 0 ≤ x ≤ 1 and 0 otherwise. Determine the mean, the variance, and the standardized variable.