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3 years ago

Show that n(n+1)(n+2) is divisible by 6Solution(

Mathematics

1 answer:

vladimir2022 [97]3 years ago

6 0

Proof by induction

Base case:

n=1: 1*2*3=6 is obviously divisible by six.

Assumption: For every n>1 n(n+1)(n+2) is divisible by 6.

For n+1:

(n+1)(n+2)(n+3)=

(n(n+1)(n+2)+3(n+1)(n+2))

We have assumed that n(n+1)(n+2) is divisble by 6.

We now only need to prove that 3(n+1)(n+2) is divisible by 6.

If 3(n+1)(n+2) is divisible by 6, then (n+1)(n+2) must be divisible by 2.

The "cool" part about this proof.

Since n is a natural number greater than 1 we can say the following:

If n is an odd number, then n+1 is even, then n+1 is divisible by 2 thus (n+1)(n+2) is divisible by 2,so we have proved what we wanted.

If n is an even number" then n+2 is even, then n+1 is divisible by 2 thus (n+1)(n+2) is divisible by 2,so we have proved what we wanted.

Therefore by using the method of mathematical induction we proved that for every natural number n, n(n+1)(n+2) is divisible by 6. QED.

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A book sold 33,200 copies in its first month. Suppose this represents 7.4% of the number of copies sold to date. How many copies

Marta_Voda [28]

Answer: 448648

Step-by-step explanation:

33,200 copies represent 7.4% of the total amount

-----------------------------------------------------

#1 33,200 ÷ 7.4%

- this is because how we get 33,200 by calculation is use the total amount and times 7.4% to get 33,200. So we are just working backwards. Since it was times before, then we divide after.

33,200÷7.4%

=33,200÷0.074

≈448648 (you can't round up when the real amount is less the exact amount)

6 0

3 years ago

Read 2 more answers

Given: AC and AE are common external tangents of G and D. BC= 123 GB=20 and AG=101. What is the measure of AC?

Solnce55 [7]

Answer:

The length of AC is 222 units.

Step-by-step explanation:

Given AC and AE are common external tangents of G and D.

BC= 123 , GB=20 and AG=101.

We have to find the measure of AC.

As, a straight line joined from the center i.e radius is perpendicular to tangent drawn. Therefore,

In ΔABG, by Pythagoras theorem

$AG^2=AB^2+BG^2$

⇒ $101^2=AB^2+20^2$

⇒ $AB^2=10201-400=9801$

⇒ AB=99 units.

Hence, AC=AB+BC=99+123=222 units.

The length of AC is 222 units.

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2 years ago

Two cars traveled equal distances in different amounts of time. Car A traveled the distance in 4 h, and Car B traveled the dista

Kamila [148]

40mph for Car B I think. 45mph for Car A. 45(mph) times 4(h) is 180(distance) and 40 times 4.5 is also 180. Sorry if I'm wrong.

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3 years ago

The amount of interest earned every year with simple interest is constant. <br>true or false

Charra [1.4K]

Answer:

True.

Step-by-step explanation:

If I = prt, They are all being multiplied together, therefor being constant.

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2 years ago

In doing so, you collect a random sample of 50 salespersons employed by his company, which is thought to be representative of sa

Deffense [45]

Answer:

$z=\frac{0.36 -0.45}{\sqrt{\frac{0.45(1-0.45)}{50}}}=-1.279$

$p_v =P(z$

And we can use the following code to find it "=NORM.DIST(-1.279,0,1,TRUE)"

Step-by-step explanation:

Assuming this complete problem: "The CEO of a software company is committed to expanding the proportion of highly qualified women in the organization's staff of salespersons. He believes that the proportion of women in similar sales positions across the country is less than 45%. Hoping to find support for his belief, he directs you to test

H0: p .45 vs H1: p < .45.

In doing so, you collect a random sample of 50 salespersons employed by his company, which is thought to be representative of sales staffs of competing organizations in the industry. The collected random sample of size 50 showed that only 18 were women.

Compute the p-value associated with this test. Place your answer, rounded to 4 decimal places, in the blank. For example, 0.3456 would be a legitimate entry."

1) Data given and notation

n=50 represent the random sample taken

X=18 represent the number of women in the sample selected

$\hat p=\frac{18}{50}=0.36$ estimated proportion of women in the sample

$p_o=0.45$ is the value that we want to test

$\alpha$ represent the significance level

z would represent the statistic (variable of interest)

$p_v$ represent the p value (variable of interest)

2) Concepts and formulas to use

We need to conduct a hypothesis in order to test the claim that the proportion of women is less than 0.45:

Null hypothesis: $p\geq 0.45$

Alternative hypothesis: $p < 0.45$

When we conduct a proportion test we need to use the z statistic, and the is given by:

$z=\frac{\hat p -p_o}{\sqrt{\frac{p_o (1-p_o)}{n}}}$ (1)

The One-Sample Proportion Test is used to assess whether a population proportion $\hat p$ is significantly different from a hypothesized value $p_o$ .

3) Calculate the statistic

Since we have all the info requires we can replace in formula (1) like this:

$z=\frac{0.36 -0.45}{\sqrt{\frac{0.45(1-0.45)}{50}}}=-1.279$

4) Statistical decision

It's important to refresh the p value method or p value approach . "This method is about determining "likely" or "unlikely" by determining the probability assuming the null hypothesis were true of observing a more extreme test statistic in the direction of the alternative hypothesis than the one observed". Or in other words is just a method to have an statistical decision to fail to reject or reject the null hypothesis.

The next step would be calculate the p value for this test.

Since is a left tailed test the p value would be:

$p_v =P(z$

And we can use the following code to find it "=NORM.DIST(-1.279,0,1,TRUE)"

4 0

3 years ago

Show that n(n+1)(n+2) is divisible by 6Solution(​

Show that n(n+1)(n+2) is divisible by 6Solution(