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2 years ago

A box contains 20 balls, of which are white. If the probability of selecting a non-white

Mathematics

1 answer:

Delicious77 [7]2 years ago

4 0

Answer:

if a box contains 20 balls in which all are white then the probability of selecting non white is 0

You might be interested in

Is 5 over 12 greater than 3 over 4

Leno4ka [110]

no, 3/4 and 5/12 can have a common denominator of 12, multiply the top and bottom by 3... 5/12 and 9/12

Hope this helped!!! :)

5 0

3 years ago

Compute the sum:

Nady [450]

You could use perturbation method to calculate this sum. Let's start from:

$S_n=\sum\limits_{k=0}^nk!\\\\\\\(1)\qquad\boxed{S_{n+1}=S_n+(n+1)!}$

On the other hand, we have:

$S_{n+1}=\sum\limits_{k=0}^{n+1}k!=0!+\sum\limits_{k=1}^{n+1}k!=1+\sum\limits_{k=1}^{n+1}k!=1+\sum\limits_{k=0}^{n}(k+1)!=\\\\\\=1+\sum\limits_{k=0}^{n}k!(k+1)=1+\sum\limits_{k=0}^{n}(k\cdot k!+k!)=1+\sum\limits_{k=0}^{n}k\cdot k!+\sum\limits_{k=0}^{n}k!\\\\\\(2)\qquad \boxed{S_{n+1}=1+\sum\limits_{k=0}^{n}k\cdot k!+S_n}$

So from (1) and (2) we have:

$\begin{cases}S_{n+1}=S_n+(n+1)!\\\\S_{n+1}=1+\sum\limits_{k=0}^{n}k\cdot k!+S_n\end{cases}\\\\\\
S_n+(n+1)!=1+\sum\limits_{k=0}^{n}k\cdot k!+S_n\\\\\\
(\star)\qquad\boxed{\sum\limits_{k=0}^{n}k\cdot k!=(n+1)!-1}$

Now, let's try to calculate sum $\sum\limits_{k=0}^{n}k\cdot k!$ , but this time we use perturbation method.

$S_n=\sum\limits_{k=0}^nk\cdot k!\\\\\\
\boxed{S_{n+1}=S_n+(n+1)(n+1)!}\\\\\\
$

but:

$S_{n+1}=\sum\limits_{k=0}^{n+1}k\cdot k!=0\cdot0!+\sum\limits_{k=1}^{n+1}k\cdot k!=0+\sum\limits_{k=0}^{n}(k+1)(k+1)!=\\\\\\=
\sum\limits_{k=0}^{n}(k+1)(k+1)k!=\sum\limits_{k=0}^{n}(k^2+2k+1)k!=\\\\\\=
\sum\limits_{k=0}^{n}\left[(k^2+1)k!+2k\cdot k!\right]=\sum\limits_{k=0}^{n}(k^2+1)k!+\sum\limits_{k=0}^n2k\cdot k!=\\\\\\=\sum\limits_{k=0}^{n}(k^2+1)k!+2\sum\limits_{k=0}^nk\cdot k!=\sum\limits_{k=0}^{n}(k^2+1)k!+2S_n\\\\\\
\boxed{S_{n+1}=\sum\limits_{k=0}^{n}(k^2+1)k!+2S_n}$

When we join both equation there will be:

$\begin{cases}S_{n+1}=S_n+(n+1)(n+1)!\\\\S_{n+1}=\sum\limits_{k=0}^{n}(k^2+1)k!+2S_n\end{cases}\\\\\\
S_n+(n+1)(n+1)!=\sum\limits_{k=0}^{n}(k^2+1)k!+2S_n\\\\\\\\
\sum\limits_{k=0}^{n}(k^2+1)k!=S_n-2S_n+(n+1)(n+1)!=(n+1)(n+1)!-S_n=\\\\\\=
(n+1)(n+1)!-\sum\limits_{k=0}^nk\cdot k!\stackrel{(\star)}{=}(n+1)(n+1)!-[(n+1)!-1]=\\\\\\=(n+1)(n+1)!-(n+1)!+1=(n+1)!\cdot[n+1-1]+1=\\\\\\=
n(n+1)!+1$

So the answer is:

$\boxed{\sum\limits_{k=0}^{n}(1+k^2)k!=n(n+1)!+1}$

Sorry for my bad english, but i hope it won't be a big problem :)

8 0

3 years ago

Bella solves the equation 4(x + p) = 12, where p is a constant. He states that solution to the equation is x = -5. Determine the

liq [111]

Answer:

P=3

Step-by-step explanation:

To solve for p, we can simply substitute his answer in place of x, changing the equation to 4(-5+p)=12. Now we just have to solve it.

1. Apply the distributive property. We can do this by multiplying 4 by -5 and p. Our equation is now -20+4p=12

2. Add 20 on both sides. Since the 20 is negative, we would add it on both sides, canceling out the -20 and leaving us with the equation 4p=32.

3. Now divide 12 by 4. We want to get p alone by itself, so we divide both sides by 4, leaving us with the solution p=3.

Hope this helps! :D

4 0

2 years ago

Solve - pv + 40 < 65 for v<br> solve 7w - 3r = 15 for r

Katarina [22]

Answer:

v > -25/p

r = -5 +7/3 w

Step-by-step explanation:

- pv + 40 < 65

Subtract 40 from each side

- pv + 40-40 < 65-40

-pv < 25

Divide each side by -p (remember to flip the inequality since we are dividing by a negative)

-pv/-p > 25/-p

v > -25/p

7w - 3r = 15

Subtract 7w from each side

7w-7w - 3r = 15-7w

-3r = 15-7w

Divide by -3

-3r/-3 = (15-7w)/-3

r = -5 +7/3 w

8 0

3 years ago

Diego Rollins is paid $10.20 an hour for a regular 40-hour week at the

Aloiza [94]

Answer:

$1632

Step-by-step explanation:

Hourly pay for Diego = $10.20

Weekly hours = 40 Hours

Basic earning = 10.20 × 40 = $408

Overtime pay = 15 × Hourly rate = 15 × 10.20 = $153

Total overtime = 8 hours

Overtime earning = 153 × 8 = 1224

Total earning for the week = 408 + 1224 = $1632

5 0

3 years ago