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3 years ago

good morning fellow brainsters please help me i’m tired and i just drank a four loko... can’t think. will give 15 points

Mathematics

1 answer:

borishaifa [10]3 years ago

4 0

Answer:

7. $x=3$

8. l=11cm and w=7 cm

9. $x-5\ge12$

10. $\frac{x}{3}\le15$

Step-by-step explanation:

Question 7.

The given expression is:

$12-3(2x+1)=7x-3(7+x)$

Expand the parenthesis using the distributive property:

$12-6x-3=7x-21-3x$

Group similar terms:

$-6x-7x+3x=-21+3-12$

Simplify

$-10x=-30$

Divide both sides by -10

$x=3$

Question 8:

Let the width of the rectangle be; $w$

The length of the rectangle is $l=w+4$

The perimeter is given as: $P=2(l+w)$

Given that the perimeter P=36, then:

$36=2[(w+4)+w)]$

$\implies 36=2(2w+4)$

Divide both sides by 2:

$\implies 18=2w+4$

Subtract 4 from both sides:

$\implies 18-4=2w$

$\implies 14=2w$

$\implies w=7$

The dimensions of the rectangle is: w=7 cm and l=7+4=11cm

Question 9

Let the number be x.

"5 fewer than the number" is written as $x-5$

"5 fewer than a number is at least 12" becomes

$x-5\ge12$

Question 10:

Let the number be x.

The quotient of a number and 3 is written as:

$\frac{x}{3}$

The quotient of a number and 3 is no more than 15 is written as;

$\frac{x}{3}\le15$

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34% of college students say they use credit cards because of the rewards program. You randomly select 10 college students and a

finlep [7]

Answer:

a) There is a 18.73% probability that exactly two students use credit cards because of the rewards program.

b) There is a 71.62% probability that more than two students use credit cards because of the rewards program.

c) There is a 82% probability that between two and five students, inclusive, use credit cards because of the rewards program.

Step-by-step explanation:

There are only two possible outcomes. Either the student use credit cards because of the rewards program, or they use for other reason. So, we can solve this problem by the binomial distribution.

Binomial probability

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

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

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

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

And $\pi$ is the probability of X happening.

In this problem, we have that:

10 student are sampled, so $n = 10$

34% of college students say they use credit cards because of the rewards program, so $\pi = 0.34$

(a) exactly two

This is P(X = 2).

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

$P(X = 2) = C_{10,2}.(0.34)^{2}.(0.66)^{8} = 0.1873$

There is a 18.73% probability that exactly two students use credit cards because of the rewards program.

(b) more than two

This is $P(X > 2)$ .

Either a value is larger than two, or it is smaller of equal. The sum of the decimal probabilities must be 1. So:

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

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

In which

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

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

$P(X = 0) = C_{10,0}.(0.34)^{0}.(0.66)^{10} = 0.0157$

$P(X = 1) = C_{10,1}.(0.34)^{1}.(0.66)^{9} = 0.0808$

$P(X = 2) = C_{10,2}.(0.34)^{2}.(0.66)^{8} = 0.1873$

$P(X \leq 2) = P(X = 0) + P(X = 1) + P(X = 2) = 0.0157 + 0.0808 + 0.1873 = 0.2838$

$P(X > 2) = 1 - P(X \leq 2) = 1 - 0.2838 = 0.7162$

There is a 71.62% probability that more than two students use credit cards because of the rewards program.

(c) between two and five inclusive

This is:

$P = P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5)$

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

$P(X = 2) = C_{10,2}.(0.34)^{2}.(0.66)^{8} = 0.1873$

$P(X = 3) = C_{10,3}.(0.34)^{3}.(0.66)^{7} = 0.2573$

$P(X = 4) = C_{10,4}.(0.34)^{4}.(0.66)^{6} = 0.2320$

$P(X = 5) = C_{10,5}.(0.34)^{5}.(0.66)^{5} = 0.1434$

$P = P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5) = 0.1873 + 0.2573 + 0.2320 + 0.1434 = 0.82$

There is a 82% probability that between two and five students, inclusive, use credit cards because of the rewards program.

6 0

3 years ago

!!Help Please!!<br> Find cos 0 20 16 12

statuscvo [17]

Answer:

the answer is 58 degrees (rounded) I have done a step by step explanation below.

Step-by-step explanation:

hope this helps...

8 0

3 years ago

HELP ME PLEASE THANK U

tangare [24]

To fine the mean for a first add up all the players heights then divide by the number of players.

Mean=(198+199+200+201+202)÷5
=1000÷5
=200

The answer to a is 200

For question be were gonna say for now that the height of our new player is represented by x. So we know that together there is 6 players and we know our answer so it should look something like this

201= (199+198+199+200+201+202+x) ÷ 6
201=1000+x ÷ 6
Then Im going to multiply 201 by 6 to get rid of the 6 on the other side.
1206=1000+x
Then I’m going to subtract 1000 from both sides to get x by itself
206=x

So the new players height is 206 .

3 0

3 years ago

How much is 3/4 of 120? And how much is 3/8 of 160?

RoseWind [281]

3/4 of 120
=3/4*120
=360/4
=90

3/8 of 160
=3/8*160
=480/8
=60

4 0

4 years ago

Read 2 more answers

Determine if 51 is rational or irrational and give a reason for your answer

Luden [163]

Answer:

irrational because the square root of 51 is irrational.

8 0

2 years ago