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rjkz [21]
3 years ago
10

If (n+1)!=90×(n-1)!,find n.​

Mathematics
1 answer:
Helen [10]3 years ago
4 0

 

\displaystyle\bf\\(n+1)!=90\times (n-1)!\\\\(n-1)!\times n\times(n+1)=90\times (n-1)!~~~\Big|~:(n-1)!\\\\n(n+1)=90\\\\n(n+1)=9\times10\\\\n(n+1)=9(9+1)\\\\\implies~~\boxed{\bf n=9}

 

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A study claims that the mean age of online dating service users is 40 years. Some researchers think this is not accurate and wan
Mademuasel [1]

Answer: H_0:\mu=40

H_0:\neq40

Step-by-step explanation:

  • A null hypothesis is a hypothesis where a researcher generally try to disprove, it says that there is no statistically significant relationship between the two variables .
  • An alternative hypothesis says that there is a statistical significance  between two variables.

Claim 1. : Mean age of online dating service users is 40 years.

i.e. \mu=40, since it has equals sign so we take this as null hypothesis.

Claim 2. : Mean age of online dating service users is not 40 years.

\mu\neq40

⇒ Null Hypothesis : H_0:\mu=40

Alternative hypothesis : H_0:\neq40

5 0
3 years ago
To make grape juice, water is added to a large cylindrical vat of grapes. If the diameter of the vat is 16 feet, what is the are
amid [387]

Answer:

200.96cm^2 base area

Step-by-step explanation:

Eq of circle area  = πr^2

= 3.14 x 8^2

  3.14 x 64

  200.96cm^2

 

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5 0
3 years ago
Hlp!
zzz [600]

Answer:

Option B

x ≥ (-5)

Step-by-step explanation:

<h3><u>Given</u>;</h3>
  • -3(x + 4) ≥ x + 8

So,

-3(x + 4) ≥ x + 8

-3x – 12 ≥ x + 8

Add both sides 12 we get,

-3x – 12 + 12 ≥ x + 8 + 12

-3x ≥ x + 20

Similarly, subtract x from both sides we get,

-3x – x ≥ x – x + 20

-4x ≥ 20

Then, divide both sides by (-4) we get,

-4x/(-4) ≥ 20/(-4)

x ≥ -5

Thus, The answer is x ≥ (-5).

7 0
2 years ago
If "-3(y-10=9" what is the value of y-12
zvonat [6]

Answer:

the correct answer is -5 since y=7

8 0
2 years ago
Read 2 more answers
Find the area, correct to the nearest square
Lady bird [3.3K]

Answer:

1269 square meters

Step-by-step explanation:

The path and the plot of land form two concentric circles (they have the same center). The radius of the plot of land is 100m (half of the diameter) and the radius of the larger circle, formed by putting a 2m wide path around the plot of land, is 102m. Thus, the area of the path is \pi *102^2 minus \pi *100^2 which will be 10404\pi-10000\pi which is 404\pi. Estimate \pi to 3.141 and calculate, getting 1268.964... which is 1269, rounded to the nearest square meter.

Hope this helps :)

7 0
2 years ago
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