The one highlighted is wrong please help

We have two types of textbooks. Let's use "x" to represent the number of math textbooks and "y" to represent the number of history textbooks.

Altogether, the bookseller sold 240 math and history textbooks. So:

x + y = 240

Now, the number of history textbooks sold was 72 less than the number of math books sold. So:

y = x - 72

Now we can substitute for y in the equation and solve:

x + y = 240

x + (x - 72) = 240

2x - 72 = 240

2x = 312

x = 156

The bookseller sold 156 math textbooks.

Since y = x - 72, he must have sold 84 history textbooks.

Let's check our answers:

x + y = 240

156 + 84 = 240

That is true, so we did get the correct answers.

Answer:

Tank is a tank and a cat is a cat.

Step-by-step explanation:

Answer:

ans

Step-by-step explanation:

possible ratios are 3:4,9:12 and 18:24

Mark me as a brain list please

Answer:

Step-by-step explanation:

12:9

8:6

4:3

16:12

24:18

48:36

Answer:

1. The 90% confidence interval for the true difference between average lifetimes for brakes using Compound 1 and brakes using Compound 2 is (-2411.84, -1332.16).

2. The point estimate for the true difference between the population means is of -1872.

Step-by-step explanation:

Before building the confidence interval, we need to understand the central limit theorem and subtraction between normal variables.

Central Limit Theorem

The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

Subtraction of Normal Variables:

When two normal variables are subtracted, the mean is the subtraction of the means while the standard deviation is the square root of the sum of the variances.

A sample of 212 brakes using Compound 1 yields an average brake life of 47,895 miles. The population standard deviation for Compound 1 is 1590 miles.

This means that [tex]\mu_1 = 47895, \sigma_1 = 1590, n = 212, s_1 = \frac{1590}{\sqrt{212}} = 109.2[/tex]

A sample of 180 brakes using Compound 2 yields an average brake life of 49,767 miles. The population standard deviation for Compound 2 is 4152 miles.

This means that [tex]\mu_2 = 49767, \sigma_2 = 4152, n = 180, s_2 = \frac{4152}{\sqrt{180}} = 309.47[/tex]

True difference between average lifetimes for brakes using Compound 1 and brakes using Compound 2.

This is the distribution 1 - 2. So

[tex]\mu = \mu_1 - \mu_2 = 47895 - 49767 = -1872[/tex]

This is also the point estimate for the true difference between the population means, which is question 2.

[tex]s = \sqrt{s_1^2+s_2^2} = \sqrt{109.2^2+309.47^2} = 328.17[/tex]

90% confidence interval

We have that to find our [tex]\alpha[/tex] level, that is the subtraction of 1 by the confidence interval divided by 2. So:

[tex]\alpha = \frac{1 - 0.9}{2} = 0.05[/tex]

Now, we have to find z in the Ztable as such z has a pvalue of [tex]1 - \alpha[/tex].

That is z with a pvalue of [tex]1 - 0.05 = 0.95[/tex], so Z = 1.645.

Now, find the margin of error M as such

[tex]M = zs = 1.645*328.17 = 539.84[/tex]

The lower end of the interval is the sample mean subtracted by M. So it is -1872 - 539.84 = -2411.84

The upper end of the interval is the sample mean added to M. So it is -1872 + 539.84 = -1332.16.

The 90% confidence interval for the true difference between average lifetimes for brakes using Compound 1 and brakes using Compound 2 is (-2411.84, -1332.16).

9514 1404 393

Answer:

  after 2 seconds

Step-by-step explanation:

We want to find t such that h = 0.

 0 = -16t² +8t +48

  0 = 2t² -t -6 . . . . . . . divide by -8

  0 = (t -2)(2t +3) . . . . factor

The only positive solution is t = 2, which makes the first factor zero.

Stella will land in the water at t = 2 seconds.

Answer:

25%

Step-by-step explanation:

Since we know that the markdown is $20 by subtracting 80-60 , we find out what percent of 20 is 80. To do that you do 20/80, which is 0.25, or 25 percent.

Answer:

x=13

Step-by-step explanation:

3(x-10)=x+4

3x-30=x-4

3x=x+26

2x=26

x=13

Answer:

Includes Steps

Step-by-step explanation:

3/4x-7 =3(1/6x+1)

3/4x-7=3/6x +3

1/4x=10

x=40

Answer:

Its also 30 degrees

Step-by-step explanation:

That shape is a vertical angle. This means that is 2 was 150 degrees, than 4 would also be 150 degrees. This means that if 1 is 30, then 3 is...... eh you get the idea. its 30 degrees.

P.S: Your welcome :)

Answer:

Wins _16____. Losses _12____.

Step-by-step explanation:

Since they played 24 games, the wins and losses must add to 24.

Wins     losses

24           0

23           1

22           2

21            3

20           4

19            5

18           6

17            7

16            8            

15            9

14            10

13            11

12           12

11            13

10           14

9           15

They won 4 more than they lost is 16 W and 12 L.

Answer:

exact form: 5/3

decimal form: 1.6 (6 is repeating)

mixed number form: 1  2/3

Step-by-step explanation:

Answer:

1 2/3

Step-by-step explanation:

1 1/4 x  1 1/3 = 5/4 x 4/3 = (5x4)/(4x3) = 20/12 = 5/3 = 1 2/3

9514 1404 393

Answer:

  13

Step-by-step explanation:

4 m is 400 cm, so the number that can be cut is ...

  (400 cm)/(30 cm/piece) = 13 1/2 pieces

13 pieces can be cut that are 30 cm long.

Answer:

13 whole pieces

Step-by-step explanation:

4m=400cm

400cm÷30cm=13.333333

you can't get 0.33333333(goes on forever) of a ribbon so its 13

hope this helps:)

Answer:

%6.8

Step-by-step explanation:

The five members of the Roberts family went to a high school soccer game. The total cost was $44.

They paid $10 less because they used a $10 coupon, how much was the cost per person?

members in the family = 5

total cost = $44

cost per person = 44/5

= $8.8

Now, they got $10 coupon so they paid $10 less.

therefore,

New total cost = $44-$10

= $34

New per person cost = $34/5

= $6.8

Answer:

they paid $8.80 cents per person without coupan but with coupon they paid $6.80

Step-by-step explanation:

i divied 44 by 5 to get $8.80 without cupon but woth coupan is subracted 34 divied by 5 and got $6.80.

Answer:

-10x-15

Step-by-step explanation:

So first we start off with 5(-2x-3)

Next, we distribute the 5 to the -2x to get -10x.

Next, we distribute the 5 to the -3 to get -15.

Therefore,

-10x-15 is correct

Answer:

-10x-15

Step-by-step explanation:

It's 10x-15, because you just need to simplify it.

It is the same thing as (5 x (-2x)) - (5 x 3), if you use the distributive property.

that is the same as -10x-15

Answer:

x=10

Step-by-step explanation:

x-1 = 9

add 1 on both side

x-1+1=9+1

x=10

Answer:

The answer would be 10

Step-by-step explanation:

1) Add 1 to both sides.

[tex]x = 9 + 1[/tex]

2) Simplify 9 + 1 to 10.

[tex]x = 10[/tex]

Hence, the answer would be 10.

x = 10

Answer:

X= -33/4

Step-by-step explanation:

Answer:

2 solutions

Step-by-step explanation:

Answer:

A. [tex] \frac{5}{6}\pi x^2 [/tex]

Step-by-step explanation:

Central angle of shaded part

[tex] \theta = 360\degree-60\degree= 300\degree[/tex]

Radius (r) = x unit

Area of the shaded part of [tex] \odot K[/tex]

[tex] = \frac{\theta}{360\degree} \times \pi r^2 [/tex]

[tex] = \frac{300\degree}{360\degree} \times \pi x^2 [/tex]

[tex] = \frac{5}{6}\pi x^2 [/tex]

Answer:

9/17

Step-by-step explanation:

there are 17 marbles in total 9 of them are blue therefore, 9/17 is the correct answer

Answer:

ds/dt = kN(N-S)

Step-by-step explanation:

Given

Total number of student = N

number of students who have seen the program = S

Number of students who have not seen the program = N-S

The product of the number of students who have seen the program and the number of students who have not seen the program = N(N-S)

If the rate of number of students who have seen a new television program increases at a rate proportional to the product of the number of students who have seen the program and the number of students who have not seen the program, then:

ds/dt = kN(N-S)

k is the proportionality constant

Answer:

$2.10

Step-by-step explanation:

8.40÷4=2.1

Therefore, the price for 1 lb of grapes is $2.10.

Answer:

15 - 2x = 3

Step-by-step explanation:

Let x be the amount of days that have passed.

15 - 2x gives the amount at any day number x.

15 - 2x = 3 represents the day when you had 3 bottles left.

Answer:

C) If the null hypothesis were true, there is a 2 percent chance of obtaining a chi-square value of at least 7.82.

Step-by-step explanation:

The value of the chi-square test statistic was 7.82 and the p- value is 0.02. This means that if the null hypothesis were true there is a 2 percent chance of obtaining a chi square value of at least 7.82

The p- value is defined as obtaining the test statistic under H0 as extreme as observed.

When the p- value is less than 0.05 in the chi square goodness fit test it means that the null hypothesis is rejected.

There fore option C is the best answer.

A)There is a 2 percent chance that the company's claim is correct.

B) There is a 2 percent chance of obtaining a chi-square value of at least 7.82.

C) If the null hypothesis were true, there is a 2 percent chance of obtaining a chi-square value of at least 7.82.

D) If the null hypothesis were true, there is a 2 percent chance that the company's claim is correct.

E)  If the null hypothesis were true, there is a 2 percent chance of obtaining a chi-square value of 7.82.

The p-value is defined as obtaining the test statistic under H₀ as extreme as observed. Then the correct option is C.

In null hypotheses, there is no relationship between the two phenomenons under the assumption or it is not associated with the group. And in alternative hypotheses, there is a relationship between the two chosen unknowns.

The value of the chi-square test statistic was 7.82 and the p-value is 0.02. This means that if the null hypothesis were true if there is a 2% chance of obtaining a chi-square value of at least 7.82.

The p-value is defined as obtaining the test statistic under H₀ as extreme as observed.

Thus, the correct option is C.

More about the null hypotheses and the alternative hypotheses link is given below.

https://brainly.com/question/9504281

Step-by-step explanation:

Slope = m

y - y° = m(x - x°)

m(x - x°) = y - y°

m = (y - y°)/(x - x°)

y intercept x = 0

... and I don't know :")

Answer:

1/4 because 25% is a quarter.

Answer:

+12 +1

Step-by-step explanation:

Answer:

an = 33n + 37

Step-by-step explanation:

I took the test.