K2R7 is correct in his response. The author stated that the draw was without replacement. Therefore, drawing 2 red balls would be (4/6)*(3/5) = .400. Drawing 2 blue balls would be (2/6) * (1/5) = .067. Add the two together equals .400 + .067 = .467. Explanation: Without replacement the number of balls (the denominator) would decrease by 1 for each subsequent draw. The first draw would have 6 balls to choose from, the second would have 5, since the ball originally chosen was 'not replaced'.