Three parts are assembled in a series so that their critical dimensions x1, x2 and x3 add. The dimensions of each part are normally distributed with the following parameters: μ1 = 100, σ1 = 4, μ2 = 75, σ2 = 4, μ3 = 75, and σ3 = 2. What is the probability that an assembly chosen at random will have a combined dimension in excess of 262?