How do I solve this

A wise man once said, "200 reduced by twice my age is 32." What is his age?

Thepotemich [5.8K]

Answer:

The man is 84

Step-by-step explanation:

84 x 2 is 168,

200-168=32

6 0

3 years ago

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PLEASE HELP FAST!

svetlana [45]

Answer:

B

Step-by-step explanation:

y × y = $y^{2}$

y × -3 = -3y

$y^{2} -3y$

4 0

3 years ago

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Show that if X is a geometric random variable with parameter p, then

Lubov Fominskaja [6]

Answer:

$\sum_{k=1}^{\infty} \frac{p(1-p)^{k-1}}{k}=-\frac{p ln p}{1-p}$

Step-by-step explanation:

The geometric distribution represents "the number of failures before you get a success in a series of Bernoulli trials. This discrete probability distribution is represented by the probability density function:"

$P(X=x)=(1-p)^{x-1} p$

Let X the random variable that measures the number os trials until the first success, we know that X follows this distribution:

$X\sim Geo (1-p)$

In order to find the expected value E(1/X) we need to find this sum:

$E(X)=\sum_{k=1}^{\infty} \frac{p(1-p)^{k-1}}{k}$

Lets consider the following series:

$\sum_{k=1}^{\infty} b^{k-1}$

And let's assume that this series is a power series with b a number between (0,1). If we apply integration of this series we have this:

$\int_{0}^b \sum_{k=1}^{\infty} r^{k-1}=\sum_{k=1}^{\infty} \int_{0}^b r^{k-1} dt=\sum_{k=1}^{\infty} \frac{b^k}{k}$ (a)

On the last step we assume that $0\leq r\leq b$ and $\sum_{k=1}^{\infty} r^{k-1}=\frac{1}{1-r}$ , then the integral on the left part of equation (a) would be 1. And we have:

$\int_{0}^b \frac{1}{1-r}dr=-ln(1-b)$

And for the next step we have:

$\sum_{k=1}^{\infty} \frac{b^{k-1}}{k}=\frac{1}{b}\sum_{k=1}^{\infty}\frac{b^k}{k}=-\frac{ln(1-b)}{b}$

And with this we have the requiered proof.

And since $b=1-p$ we have that:

$\sum_{k=1}^{\infty} \frac{p(1-p)^{k-1}}{k}=-\frac{p ln p}{1-p}$

4 0

3 years ago

explain why in a drawer only containing two different colors of socks one must pull 3 out to find a matching pair?

Lorico [155]

If there are only two colors (let's say blue and red), here's what can happen:
sock #1 is blue
#2 is either blue or red. If blue, it matches #1 and you have a pair.
if red, go to #3
#3-either blue or red. If blue, matches #1. If red, matches #2.

OR sock #1 is red... then just reverse the colors. Basically, if you have three things that can only be in two groups, then even if two of them are different, the last one has to match one of them.

8 0

3 years ago

Factorize the pynomial f(x)=x³-7x-6 completely

Makovka662 [10]

Answer:

gzgkvxgujdruutdtuhfdykjzfuk

4 0

3 years ago