The expression is 4*sqrt(30). Work Shown: Let's define circles P and Q with P representing the area of the circle with a radius of 19 and Q for a radius of 29. By using A = π*r², P calculates to 361π and Q to 841π. The resultant shaded area between circles P and Q is R = Q - P, which amounts to 480π. To ascertain the radius of a new circle S that would equal this area, we simplify R = 480π to find r = sqrt(480) leading us to r = 4*sqrt(30).
Given there are equal amounts of each color and four colors in total, the probability is calculated out of four. As there's an equal quantity of both red and blue, the chance of drawing either a red or blue marble is 2/4.