OK so you want the probabilty of A and B occurring. Independet event probabilities are multiplied so its 0.2 * 0.6 = 0.12
b
The greatest number of robots: 74999
The least number of robots: 74499
First find the radius by taking half the diameter. Use the radius to find the base area by using the formula for the area of a circle. Find the product of the base area and height, and then take one-third of the product.