Carlos has chosen twelve different compact discs (CDs) he would like to buy. Four are rap music, five are country music, and three are heavy metal music. Carlos then randomly selects five of the 12 CDs to purchase. What is the probability that his purchase includes at least one CD from each of the three categories

185/198

Step-by-step explanation:

Since the are 12 Cd and we require them to be selected in 5 ways, the number of selections is ¹²C₅ = 12 × 11 × 10 × 9 × 8/5! = 95040/120 = 792 ways

Since we have Four are rap music, five are country music, and three are heavy metal music, the number of ways to select them in groups of five so as to have at least one of each CD from each category, we have

For the first selection 3 of one category, and 1 each of the other categories.

The second selection is 2 each of two categories and 1 of the last category.

So, doing this for each category, we have

⁴C₃ × ⁵C₁ × ³C₁ + ⁴C₂ × ⁵C₂ × ³C₁ + ³C₃ × ⁴C₁ × ⁵C₁ + ³C₂ × ⁴C₂ × ⁵C₁ + ⁵C₃ × ⁴C₁ × ³C₁ + ⁵C₂ × ³C₂ × ⁴C₁

= (4 × 3 × 2/3! × 5 × 3) + (4 × 3/2! × 5 × 4/2! × 3) + (1 × 4 × 5) + (3 × 2/2! × 4 × 3/2! × 5) + (5 × 4 × 3/2! × 4 × 3) + (5 × 4/2! × 3 × 2/2! × 4)

= 360/6 + 720/4 + 20 + 360/4 + 720/2 + 120/4

= 60 + 180 + 20 + 90 + 360 + 30

= 740 ways

So, the required probability is P = number of ways of selecting at least one CD/ total number of ways = 740/792 = 185/198

option a.

step-by-step explanation:

if you look closely at the graph, we can notice that the function is not defined at two different points.

if you look at functions b and c, you will notice that both functions are not defined at just one point. the function b is not defined at x= -5/2 and function c is not defined at x=-5. both options are discarded, given that our function should not be defined at two fiferent points.

now, if you look closely at the graph you will notice that the function sketched is not defined at x=5 and x=-2.