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3 years ago

Find the cardinal number of the set:

Mathematics

1 answer:

yarga [219]3 years ago

8 0

Answer: 6

Step-by-step explanation:

Ok lemme actually format this set

$C = \left\{\frac 1x : x \in \mathbb{Z}\ \text{and}\ 4 \leq x \leq 9\right\}$

Well the only integers from 4 to 9 are 4, 5, 6, 7, 8, 9. So this set is just

$C = \left\{\frac 14, \frac 15, \frac 16, \frac 17, \frac 18, \frac 19\right\}$

which has cardinality $\boxed{6}$ .

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A multiple choice exam has ten questions. Each question has five possible answers, of which one is correct. Suppose that a stude

Ber [7]

Answer:

8.81% probability that the student answers exactly 4 questions correctly

Step-by-step explanation:

For each question, there are only two possible outcomes. Either he answers it correctly, or he does not. The probability of answering a question correctly is independent of other questions. So we use the binomial probability distribution to solve this question.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

In which $C_{n,x}$ is the number of different combinations of x objects from a set of n elements, given by the following formula.

$C_{n,x} = \frac{n!}{x!(n-x)!}$

And p is the probability of X happening.

A multiple choice exam has ten questions.

This means that $n = 10$

The probability of answering any question correctly is 0.20.

This means that $p = 0.2$

What is the probability that the student answers exactly 4 questions correctly

This is P(X = 4).

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 4) = C_{10,4}.(0.2)^{4}.(0.8)^{6} = 0.0881$

8.81% probability that the student answers exactly 4 questions correctly

4 0

4 years ago

My fourth number is 39 my fifth number is 43 what is my first number ?

Stells [14]

Answer:

Step-by-step explanation:

39+4=43

27, 31, 35, 39, 43

7 0

3 years ago

Read 2 more answers

three friends Run a 10 mile relay each person runs an equal amount what fraction of the relay does each person run

Anon25 [30]

Hey there!

Since there are 3 friends running an equal amount of this relay race, each will run 1/3 of the relay.

This is because 3 thirds make a whole, and each third is equal to the others, so if you add each distance ran by each of the friends, or simply multiply each portion by 3, you'd get 10 miles.

If you're also looking for how long each friend runs, which I know isn't in the question but I'll add it anyways, it is 3 1/3 miles. This can be found by dividing 10 into 3 equal parts.

Hope this helps!

6 0

3 years ago

What is 254 divided by 40

Zigmanuir [339]

The answer is 6.35. Because you put in 254 / 40 and it says 6.35.

8 0

3 years ago

Read 2 more answers

Um i dont know the answer to this pls help

lorasvet [3.4K]

Answer: