Answer:
It would be helpful if you show me the figure. Thanks :) !!
Answer:
4
Step-by-step explanation:
Let's say B is the number of boys and T is the number of teachers.
T / (B + 18) = 2/21
B/18 = 4/3
Solve the second equation for B.
B = 24
Plug into the first equation to find T.
T / (24 + 18) = 2/21
T = 4
Answer: 20
Step-by-step explanation:
Answer: Our required probability is 0.3387.
Step-by-step explanation:
Since we have given that
Number of red cards = 4
Number of black cards = 5
Number of cards drawn = 5
We need to find the probability of getting exactly three black cards.
Probability of getting a black card = 
Probability of getting a red card = 
So, using "Binomial distribution", let X be the number of black cards:

Hence, our required probability is 0.3387.