Assuming a standard deviation of $110 and normal distribution for domestic airfare, and a mean cost of $385, P ( Z > x ) = 0.03 Value of z to the cumulative probability of 0.03 from normal table is 1.88 P( x-u/ (s.d) > x - 385/110) = 0.03 That is, ( x - 385/110) = 1.88 --> x = 1.88 * 110+385 = 591.91