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3 years ago

One number is 3 less than 4 times a second number. The difference of the

Mathematics

1 answer:

s344n2d4d5 [400]3 years ago

3 0

Answer:

17 and 5

Step-by-step explanation:

Interesting question!

Turn both sentences to equations:

$a=4b-3\\a-2b=7$

a is the first number, and b is the second number.

A system of equations! A graphing calculator will do the work:

(See picture)

The y in the picture is a, and the x in the picture is b.

So the solution is a=17 and b=5

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What's the cube root of 2744000

Paraphin [41]

The cube root of 2744000 is 140

4 0

4 years ago

crystal is picking blueberries.so far,she has filled 2/3 of her basket,and the blueberries weigh 3/4pound .the equation 2/3w=3/4

vesna_86 [32]

In order to do this, we multiply both sides be the amount that would make the left side equal to 1. This number is the reciprocal of the fraction, so we multiply both sides by 3/2. This is equal to:

w = 9/8

So, the blueberries in crystal's basket will weigh 9/8 pounds when it is full.

7 0

3 years ago

a math teacher claims that she has developed a review course that increases the score of students on the math portion of a colle

madam [21]

Answer:

$H_0: \mu\leq514\\\\H_1: \mu>514$

B. Z=2.255. P=0.01207.

C. Although it is not big difference, it is an improvement that has evidence. The scores are expected to be higher in average than without the review course.

D. P(z>0.94)=0.1736

Step-by-step explanation:

A. state the null and alternative hypotheses.

The null hypothesis states that the review course has no effect, so the scores are still the same. The alternative hypothesis states that the review course increase the score.

$H_0: \mu\leq514\\\\H_1: \mu>514$

B. test the hypothesis at the a=.10 level of confidence. is a mean math score of 520 significantly higher than 514? find the test statistic, find P-value. is the sample statistic significantly higher?

The test statistic Z can be calculated as

$Z=\frac{M-\mu}{s/\sqrt{N}} =\frac{520-514}{119/\sqrt{2000}}=\frac{6}{2.661}=2.255$

The P-value of z=2.255 is P=0.01207.

The P-value is smaller than the significance level, so the effect is significant. The null hypothesis is rejected.

Then we can conclude that the score of 520 is significantly higher than 514, in this case, specially because the big sample size.

C. do you think that a mean math score of 520 vs 514 will affect the decision of a school admissions adminstrator? in other words does the increase in the score have any practical significance?

Although it is not big difference, it is an improvement that has evidence. The scores are expected to be higher in average than without the review course.

D. test the hypothesis at the a=.10 level of confidence with n=350 students. assume that the sample mean is still 520 and the sample standard deviation is still 119. is a sample mean of 520 significantly more than 514? find test statistic, find p value, is the sample mean statisically significantly higher? what do you conclude about the impact of large samples on the p-value?

In this case, the z-value is

$Z=\frac{520-514}{s/\sqrt{n}} =\frac{6}{119/\sqrt{350}} =\frac{6}{6.36} =0.94\\\\P(z>0.94)=0.1736>\alpha$

In this case, the P-value is greater than the significance level, so there is no evidence that the review course is increasing the scores.

The sample size gives robustness to the results of the sample. A large sample is more representative of the population than a smaller sample. A little difference, as 520 from 514, but in a big sample leads to a more strong evidence of a change in the mean score.

Large samples give more extreme values of z, so P-values that are smaller and therefore tend to be smaller than the significance level.

8 0

3 years ago

PLEASE HELP PLA

aleksley [76]

Answer:

$y = -x+8$