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3 years ago

When the second equation is subtracted from the first the resulting equation is

Mathematics

1 answer:

skelet666 [1.2K]3 years ago

5 0

To find this answer, we subtract each of the like terms in the equation. 3x and 3x are like terms, -4y and 2y are like terms, and 7 and -5 are like terms. Now we subtract. 3x - 3x is 0, -4y - 2y is -6y, and 7 - (-5) is 12. That means that the result is -6y = 12, or B.

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A multiple-choice examination has 15 questions, each with five answers, only one of which is correct. Suppose that one of the st

Alex

Answer:

0.0111% probability that he answers at least 10 questions correctly

Step-by-step explanation:

For each question, there are only two outcomes. Either it is answered correctly, or it is not. The probability of a question being answered correctly is independent from 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 examination has 15 questions, each with five answers, only one of which is correct.

This means that $n = 15, p = \frac{1}{5} = 0.2$

What is the probability that he answers at least 10 questions correctly?

$P(X \geq 10) = P(X = 10) + P(X = 11) + P(X = 12) + P(X = 13) + P(X = 14) + P(X = 15)$

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

$P(X = 10) = C_{15,10}.(0.2)^{10}.(0.8)^{5} = 0.0001$

$P(X = 11) = C_{15,11}.(0.2)^{11}.(0.8)^{4} = 0.000011$

$P(X = 12) = C_{15,12}.(0.2)^{12}.(0.8)^{3} \cong 0$

$P(X = 13) = C_{15,13}.(0.2)^{13}.(0.8)^{2} \cong 0$

$P(X = 14) = C_{15,14}.(0.2)^{14}.(0.8)^{1} \cong 0$

$P(X = 15) = C_{15,15}.(0.2)^{15}.(0.8)^{0} \cong 0$

$P(X \geq 10) = P(X = 10) + P(X = 11) + P(X = 12) + P(X = 13) + P(X = 14) + P(X = 15) = 0.0001 + 0.000011 = 0.000111$

0.0111% probability that he answers at least 10 questions correctly

3 0

3 years ago

Robert is 10 years older than her brother. In 2 years, Robert will be three times as old as his brother. How old are they now?

valentina_108 [34]

Robert is 13 and his brother is 3 y.o.
X... brother’s age
X+10... Robert’s age
X+10+2... Robert’s age in 2 years
X+2...Brother’s age in 2 years
X+10+2/x+2=3
X=3
X+10=13

6 0

4 years ago

Norman makes $15 commission for selling $200 in merchandise. he makes $37.50 commission for selling $500 in merchandise. assumin

vladimir2022 [97]

So he needs to sell $2,000 in merchandise.

<h3>what is the total value of merchandise he needs to sell?</h3>

We can assume that we have a proportional relation:

y = k*x

Where y is the commission and x is what Norman sells, then:

$15 = k*$200

k = $200/$15 = 0.075

$37.50 = k*$500

k = $500/$37.50 = 0.075

Then the relation is:

y = 0.075*x

If he wants a commission of $150, then:

$150 = 0.075*x

$150/0.075 = x = $2,000

So he needs to sell $2,000 in merchandise.

If you want to learn more about proportional relationships:

brainly.com/question/12242745

#SPJ1

3 0

2 years ago

Given f(x) = 15x + 35, what is the domain of f?

xeze [42]

All real values of x

5 0

4 years ago

Read 2 more answers

Question 7 of 10<br> What is the solution to this equation

tatyana61 [14]

Answer:

x = 4

Step-by-step explanation:

x + 4(x+5) = 40 (Given)

x + 4x + 20 = 40 (Distribute the 4 into the x and 5)

5x + 20 = 40 (Add like terms)

5x = 20 (Subtract 20 on both sides)

x = 4 (Divide 5 on both sides)

5 0

3 years ago