Answer:
I dont think you pasted the answer right... If you comment i can try and help you
Step-by-step explanation:
You can extract two balls of the same colour in two different way: either you pick two black balls or two red balls. Let's write the probabilities of each pick in each case.
Case 1: two black balls
The probability of picking the first black ball is 2/5, because there are two black balls, and 5 balls in total in the urn.
The probability of picking the second black ball is 1/4, because there is one black ball remaining in the urn, and 4 balls in total (we just picked the other black one!)
So, the probability of picking two black balls is

Case 2: two red balls
The probability of picking the first black ball is 3/5, because there are three red balls, and 5 balls in total in the urn.
The probability of picking the second red ball is 2/4=1/2, because there are two red balls remaining in the urn, and 4 balls in total (we just picked the other red one!)
So, the probability of picking two red balls is

Finally, the probability of picking two balls of the same colour is

Answer:
144.
The reason is because 1 ft = 12 in, (1 ft)2 = (12 in)2 = 144 in2.
Seven halves would equal to 3.5 wholes. What you do is divide 7 by 2 to find out how many wholes their are.