How many 9 digit combinations with 10 numbers?

1 answer:

3 0

<span>There are 1 billion 9 digit numbers (000,000,000 through 999,999,999). There are 45 different combinations of two different numerals (10 x 9 divided by 2). There are 512 (2 to the 9th power) different permutations for any two numbers to be used in a 9 digit number</span>

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A bedroom has the shape shown. The homeowner is upgrading by putting in new crown molding. How many feet of crown molding does s

Ivahew [28]

Answer: D.

Step-by-step explanation: Add all of the sides' lengths together. The rest of the wall beneath where "5 ft." is measures as 6 ft. Add that to the 5 ft of the rest of the wall and you'll have 11 for the whole right wall. Add 11 to 8, 10 and 12, and you'll have 41 which is close to the last choice so you're safest bet is D.

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4 years ago

a business has recently made some upgrades to their shop that cost them $1,200. Normally, this business has a running cost of $5

DedPeter [7]

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9.23 hours to recover the money spent.

Step-by-step explanation:

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Use the cross product to find the sin(θ) where θ is the angle between v and w where v=i+j and w=i+j+k.

romanna [79]

$\|\mathbf v\times\mathbf w\|=\|\mathbf v\|\|\mathbf w\|\sin\theta$

$\mathbf v\times\mathbf w=\begin{vmatrix}\mathbf i&\mathbf j&\mathbf k\\1&1&0\\1&1&1\end{vmatrix}$
$\mathbf v\times\mathbf w=\begin{vmatrix}1&0\\1&1\end{vmatrix}\mathbf i-\begin{vmatrix}1&0\\1&1\end{vmatrix}\mathbf j+\begin{vmatrix}1&1\\1&1\end{vmatrix}\mathbf k$

$\mathbf v\times\mathbf w=\mathbf i-\mathbf j$
$\implies\|\mathbf v\times\mathbf w\|=\sqrt{1^2+(-1)^2}=\sqrt2$

$\mathbf v=\sqrt{1^2+1^2}=\sqrt2$
$\mathbf w=\sqrt{1^2+1^2+1^2}=\sqrt3$

$\sqrt 2=\sqrt2\cdot\sqrt3\sin\theta$
$\dfrac1{\sqrt3}=\sin\theta$