Questions

At least one black can be chosen in two ways from each box:
Now, probability of choosing at least one black ball from first box 

= 1/2 × [ (2C1× 2C1)/4C2 + 2C2/ 4C2 ]= 5/12

Probability of choosing at least one black ball from 2nd box
= 1/2 × [(4C1×12C1)/16C2 + 4C2/ 16C2] = 9/40

Final probability

= 5/12 + 9/40 = (50 + 27)/120 = 77/120

Competition  occurs when two or more organisations act independently to supply their products to the same group of consumers.

There are mainly two cases when firms can compete. One is price where firms are selling identical or very similar products, they must compete on price with each firm trying to undercut the others. The other is differentiation. A non-price competition depends on making a product different from those of competitors and by giving it distinctive qualities that are valued by the target market. This might include branding, styling, special features or higher levels of customer service. Good competition provides more options to customers and also brings with it improved  customer services.