It is necessary when you are getting into multiplying from the outside of parenthesis and multiplying variables inside of parenthesis.
ex: 5(3 + 3x)
5 * 3 = 15
5 * 3x = 15x
so final set up would be 15 + 15x
84 kilometers ... 1 hour
7 kilometers ... x hours = ?
If you would like to know how long does the pigeon take to fly 7 kilometers, you can calculate this using the following steps:
84 * x = 1 * 7
84 * x = 7 /84
x = 7/84
x = 1/12 hour
Result: A pigeon can fly 7 kilometers in 1/12 hour.
Answer:
a because a variable cannot be a variable
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.
Answer: Stratified Random Sampling
Step-by-step explanation: Got it right