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3 years ago

Select a counter-example that makes the conclusion false.

2 answers:

6 0

While none of these examples can be used as an counterexample i could make one up to prove the conclusion is false. ex: 3-5=-2

Gekata [30.6K]3 years ago

4 0

Answer:

It is not necessary that the difference of two positive number is always positive.

Step-by-step explanation:

We are given the following conclusion:

The difference between two positive number is always positive.

We have to provide a counter example to show that this conclusion is false.

It is not necessary that the difference is always positive.

The given examples are :

7 -3 = 4

8 - 5 = 3

9 - 8 = 1

The counter examples can be of the form:

3 - 7 = -4

5 - 8 = -3

8 - 9 = -1

2 - 8 = -6

Thus, we can always find a pair of positive numbers whose difference is negative.

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3 years ago

Read 2 more answers

Ms. Carter is purchasing books for her class. She needs to buy 24books. Each costs $3.45. How much money will Ms. Carter spend o

7nadin3 [17]

Answer: $282.88

Step-by-step explanation: $3.45 times 24 is $282.88

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3 years ago

On Saturday, Tom is paid $12.75 an hour plus a Saturday bonus of $25. Sara is paid $11.75 an hour plus a bonus of $29. For how l

iVinArrow [24]

Answer:

They must work for more than 4 hours for Tom's bonus to be greater than Sara's

Step-by-step explanation:

Tom pay: 12.75x+25

Sara pay: 11.75x+29

Tom>Sara = 12.75x+25>11.75x+29

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7 0

3 years ago

A 168-cm tall person is 2 cm in Ming’s model. How high should his model swing be if the actual swing is 231 cm high?

serious [3.7K]

Answer:

The model swing should be 2.75 cm high.

Step-by-step explanation:

Given:

A 168-cm tall person is 2 cm in Ming’s model.

If the actual swing is 231 cm high.

Now, to find how high should his model swing be.

Let the model swing be $x\ cm.$

So, 168 cm tall person is equivalent to 2 cm.

Thus, 231 cm actual swing is equivalent to $x\ cm$ model swing.

Now, we get the height of the swing in the model by using cross multiplication method:

$\frac{168}{2} =\frac{231}{x}$

By cross multiplication:

⇒ $168x=462$

Dividing both sides by 168 we get:

⇒ $x=2.75\ cm.$

Therefore, the model swing should be 2.75 cm high.

3 0

4 years ago

Suppose it is known that 8 out of the 20 teams in the sample had a season winning percentage better than 0.500.

Ganezh [65]

Answer:

The 95% confidence interval for the true proportion of all teams that had a season winning percentage better than 0.500 is (0.1853, 0.6147).

Step-by-step explanation:

In a sample with a number n of people surveyed with a probability of a success of $\pi$ , and a confidence interval $1-\alpha$ , we have the following confidence interval of proportions.

$\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}$

In which

Z is the zscore that has a pvalue of $1 - \frac{\alpha}{2}$ .

For this problem, we have that:

8 out of the 20 teams in the sample had a season winning percentage better than 0.500. This means that $n = 20, \pi = \frac{8}{20} = 0.4$ .

95% confidence interval

So $\alpha = 0.05$ , z is the value of Z that has a pvalue of $1 - \frac{0.05}{2} = 0.975$ , so $Z = 1.96$ .

The lower limit of this interval is:

$\pi - z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.4 - 1.96\sqrt{\frac{0.6*0.4}{20}} = 0.1853$

The upper limit of this interval is:

$\pi + z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.4 + 1.96\sqrt{\frac{0.6*0.4}{20}} = 0.6147$

The 95% confidence interval for the true proportion of all teams that had a season winning percentage better than 0.500 is (0.1853, 0.6147).

3 0

4 years ago