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3 years ago

Which of the following represents the sentence shown? “Twice a number, n, decreased by six is fourteen.”

1 answer:

8 0

Twice the number n will be expressed as 2n. So, that will be in our final answer. In order to decrease the number by 6, we will subtract 6. So there will be a - 6 in our final answer. Together, this is 2n - 6, and that is the same as the second option. So, the second option is the correct one.

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"A cash drawer contains 29 bills, all twenties and fifties. If the total value of the bills is $820, how many twenties and how m

maks197457 [2]

Answer:

There are 21 twenties and 8 fifties in the drawer.

Step-by-step explanation:

This question can be solved by a system of equations.

I am going to say that:

x is the number of twenties

y is the number of fifties.

A cash drawer contains 29 bills.

This means that x + y = 29.

The total value of the bills is $820.

This means that 20x + 50y = 820.

x + y = 29

20x + 50y = 820

From the first equation, x = 29 - y. So:

20x + 50y = 820

20(29 - y) + 50y = 820

580 - 20y + 50y = 820

30y = 240

y = 8

And

x = 29 - y = 29 - 8 = 21

There are 21 twenties and 8 fifties.

3 0

4 years ago

Read 2 more answers

Write the equation of the line that passes through these two points

Slav-nsk [51]

Answer:

am not sure of my answer ohhhh

7 0

3 years ago

If b is the midpoint of ac and if c is the midpoint of bd, then what percent of cd is ac

Sergeu [11.5K]

Answer:

ac is 200% of cd

Step-by-step explanation:

To answer this question, we shall be making a visual representation.

Let’s take it one at a time.

Given;

b is the midpoint of ac

a b c

What this means is that a-b represents 50%, while bc represents another 50%

okay, we move on:

c is the midpoint of bd

b c d

What this means is that bc is 50%, while cd is another 50%.

So let’s combine the representations;

a 50% b 50% c 50% d

Now what does the question says again?

What percent of cd is ac?

From a to c, we can see two 50% which means 100%

while cd is just the regular 50%

So we can see that ac is actually twice cd

What we are saying here is , if cd is x, then ac is 2x

So we can restructure our question to mean, what percent of x is 2x?

That is simply 2x/x * 100 and that is 200%

7 0

3 years ago

Read 2 more answers

Can someone help with number 8 please

HACTEHA [7]

Answer: Answer is -6 :-DD

Step-by-step explanation:

4 0

3 years ago

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A Statistics professor has observed that for several years students score an average of 114 points out of 150 on the semester ex

kirill [66]

Answer:

Reject $H_0$ . The change is statistically significant. The software does appear to improve exam scores.

Step-by-step explanation:

We are given that a Statistics professor has observed that for several years students score an average of 114 points out of 150 on the semester exam. The software is expensive, and the salesman offers to let the professor use it for a semester to see if the scores on the final exam increase significantly.

In the trial course that used this software, 218 students scored an average of 117 points on the final with a standard deviation of 8.7 points.

Let $\mu$ = mean scores on the final exam.

SO, Null Hypothesis, $H_0$ : $\mu \leq$ 114 points {means that the mean scores on the final exam does not increases after using software}

Alternate Hypothesis, $H_A$ : $\mu$ > 114 points {means that the mean scores on the final exam increase significantly after using software}

The test statistics that will be used here is One-sample t test statistics as we don't know about the population standard deviation;

T.S. = $\frac{\bar X -\mu}{\frac{s}{\sqrt{n} } }$ ~ $t_n_-_1$

where, $\bar X$ = sample average points = 117 points

s = sample standard deviation = 8.7 points

n = sample of students = 218

So, test statistics = $\frac{117-114}{\frac{8.7}{\sqrt{218} } }$ ~ $t_2_1_7$

= 5.091

Now, P-value of the test statistics is given by the following formula;

P-value = P( $t_2_1_7$ > 5.091) = Less than 0.05%

Since, in the question we are not given with the level of significance at which hypothesis can be tested, so we assume it to be 5%. Now at 5% significance level, the t table gives critical value of 1.645 at 217 degree of freedom for right-tailed test. Since our test statistics is higher than the critical value of t as 5.091 > 1.645, so we have sufficient evidence to reject our null hypothesis as it will fall in the rejection region due to which we reject our null hypothesis.

Therefore, we conclude that the change is statistically significant. The software does appear to improve exam scores.

3 0

3 years ago