All categories

3 years ago

Please help, need asap

Mathematics

1 answer:

MakcuM [25]3 years ago

6 0

Answer:

x= 1

y= 3

Step-by-step explanation:

21(-2+y) +7y = 42

-42 +28y+42

28y = 42+42

28y= 84

divide both sides y= 3

x= -2+3 x=1

x= + (3-2) = 1

42=42

10=10

You might be interested in

Container A has 200 L of water, and is being filled at a rate of 6 liters per minute. Container B has 500 L of water, and is bei

pickupchik [31]

Answer:

25 minutes

Step-by-step explanation:

Container A : $200 + 6x = y$

Container B: $500 - 6x = y$

y = final volume of water

x = number of minutes

Final volume is same so:

$200 + 6x = 500 - 6x\\12x = 300\\x = 25$

6 0

3 years ago

Take a guess: A student takes a multiple-choice test that has 9 questions. Each question has four choices. The student guesses r

skad [1K]

Answer:

a) P(4) = 0.1168

b) P(More than 2) = 0.3993

Step-by-step explanation:

For each question, there are only to possible outcomes. Either the students guesses the correct answer, or he guesses the wrong. Each question 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.

9 questions.

This means that $n = 9$

Each question has four choices.

This means that $p = \frac{1}{4} = 0.25$

(a) Find P(4).

This is P(X = 4).

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

$P(X = 4) = C_{9,4}.(0.25)^{4}.(0.75)^{5} = 0.1168$

P(4) = 0.1168

(b) Find P (More than 2).

Either the student answers 2 or less questions correctly, or the student answers more than 2 correctly. The sum of the probabilities of these events is 1. Then

$P(X \leq 2) + P(X > 2) = 1$

We want $P(X > 2)$ . Then

$P(X > 2) = 1 - P(X \leq 2)$

In which

$P(X \leq 2) = P(X = 0) + P(X = 1) + P(X = 2)$

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

$P(X = 0) = C_{9,0}.(0.25)^{0}.(0.75)^{9} = 0.0751$

$P(X = 1) = C_{9,1}.(0.25)^{1}.(0.75)^{8} = 0.2253$

$P(X = 2) = C_{9,2}.(0.25)^{2}.(0.75)^{7} = 0.3003$

$P(X \leq 2) = P(X = 0) + P(X = 1) + P(X = 2) = 0.0751 + 0.2253 + 0.3003 = 0.6007$

$P(X > 2) = 1 - P(X \leq 2) = 1 - 0.6007 = 0.3993$

Then

P(More than 2) = 0.3993

8 0

4 years ago

One half of the students in a school are girls, 3/5 of these girls are studying in lower classes. What fraction of girls are stu

andrew-mc [135]

Answer:

Step-by-step explanation:

6 0

3 years ago

Gary spent 1/6 of his money on baseball cards, 3/10 of the remaining on candy and save the rest. If he spent $6 on baseball card

avanturin [10]

Answer: $36

Step-by-step explanation:

Let the total amount of money that he had in the beginning be represented by x.

Since Gary spent 1/6 of his money on baseball cards which was $6. This will then be solved further as:

1/6 × x = 6

1/6x = 6

x = 6 × 6

x = 36

The total amount of money that he had in the beginning was $36

8 0

3 years ago

When it comes to positive and negative sign if two sign are the same they’re negative right and if they are different they are p

KatRina [158]

Answer:

When you have two negative signs, one turns over, and they add together to make a positive. If you have a positive and a negative, there is one dash left over, and the answer is negative.

<em>I hope this was the answer you were looking for - Lily~Senpai :P</em>

4 0

3 years ago