there are (3^2)^4 ⋅ 3^0 bacteria in a petri dish. what is the total number of bacteria in the dish? 3^8 3^9 3^11 3^24

Please help, my brain just sucks rn. The area of a rectangle is 93.6 square inches. If the length of one of its sides is 5.2 in.

snow_tiger [21]

46.4 inch

Step-by-step explanation:

Area=l×b

93.6 =5.2×b

93.6/5.2 =b

So b= 18

Again,

p=2(l+b)

p=2(18+5.2)

p= 2×23.2

p=46.4

3 0

3 years ago

Can someone please help????? What is 25% off of $23.99???

Anika [276]

$p\%=\frac{p}{100}\\\\25\%=\frac{25}{100}=\frac{1}{4}\\\\25\%\ of \ \$23.99=\frac{1}{4}\cdot\$23.99=\$5.9975\approx\$6.00$

4 0

3 years ago

A random variable X with a probability density function () = {^-x > 0

Sliva [168]

The solutions to the questions are

The probability that X is between 2 and 4 is 0.314
The probability that X exceeds 3 is 0.199
The expected value of X is 2
The variance of X is 2

<h3>Find the probability that X is between 2 and 4</h3>

The probability density function is given as:

f(x)= xe^ -x for x>0

The probability is represented as:

$P(x) = \int\limits^a_b {f(x) \, dx$

So, we have:

$P(2 < x < 4) = \int\limits^4_2 {xe^{-x} \, dx$

Using an integral calculator, we have:

$P(2 < x < 4) =-(x + 1)e^{-x} |\limits^4_2$

Expand the expression

$P(2 < x < 4) =-(4 + 1)e^{-4} +(2 + 1)e^{-2}$

Evaluate the expressions

P(2 < x < 4) =-0.092 +0.406

Evaluate the sum

P(2 < x < 4) = 0.314

Hence, the probability that X is between 2 and 4 is 0.314

<h3>Find the probability that the value of X exceeds 3</h3>

This is represented as:

$P(x > 3) = \int\limits^{\infty}_3 {xe^{-x} \, dx$

Using an integral calculator, we have:

$P(x > 3) =-(x + 1)e^{-x} |\limits^{\infty}_3$

Expand the expression

$P(x > 3) =-(\infty + 1)e^{-\infty}+(3+ 1)e^{-3}$

Evaluate the expressions

P(x > 3) =0 + 0.199

Evaluate the sum

P(x > 3) = 0.199

Hence, the probability that X exceeds 3 is 0.199

<h3>Find the expected value of X</h3>

This is calculated as:

$E(x) = \int\limits^a_b {x * f(x) \, dx$

So, we have:

$E(x) = \int\limits^{\infty}_0 {x * xe^{-x} \, dx$

This gives

$E(x) = \int\limits^{\infty}_0 {x^2e^{-x} \, dx$

Using an integral calculator, we have:

$E(x) = -(x^2+2x+2)e^{-x}|\limits^{\infty}_0$

Expand the expression

$E(x) = -(\infty^2+2(\infty)+2)e^{-\infty} +(0^2+2(0)+2)e^{0}$

Evaluate the expressions

E(x) = 0 + 2

Evaluate

E(x) = 2

Hence, the expected value of X is 2

<h3>Find the Variance of X</h3>

This is calculated as:

V(x) = E(x^2) - (E(x))^2

Where:

$E(x^2) = \int\limits^{\infty}_0 {x^2 * xe^{-x} \, dx$

This gives

$E(x^2) = \int\limits^{\infty}_0 {x^3e^{-x} \, dx$

Using an integral calculator, we have:

$E(x^2) = -(x^3+3x^2 +6x+6)e^{-x}|\limits^{\infty}_0$

Expand the expression

$E(x^2) = -((\infty)^3+3(\infty)^2 +6(\infty)+6)e^{-\infty} +((0)^3+3(0)^2 +6(0)+6)e^{0}$

Evaluate the expressions

E(x^2) = -0 + 6

This gives

E(x^2) = 6

Recall that:

V(x) = E(x^2) - (E(x))^2

So, we have:

V(x) = 6 - 2^2

Evaluate

V(x) = 2

Hence, the variance of X is 2

Read more about probability density function at:

brainly.com/question/15318348

#SPJ1

<u>Complete question</u>

A random variable X with a probability density function f(x)= xe^ -x for x>0\\ 0& else

a. Find the probability that X is between 2 and 4

b. Find the probability that the value of X exceeds 3

c. Find the expected value of X

d. Find the Variance of X

7 0

2 years ago

Find both solutions for the variable b^2+ 9b+ 18=0

Paul [167]

If you would like to solve the equation b^2 + 9 * b + 18 = 0 for the variable b, you can do this using the following step:

b^2 + 9 * b + 18 = 0
(b + 3) * (b + 6) = 0

Result:
1. solution: b = - 3
2. solution: b = - 6

7 0

3 years ago

Fazio chooses a jersey at random and then replaces it. He then selects a second jersey at random. What is the probability that f

Natalka [10]

Answer:

4% probability that fazio selects a striped jersey both times.

Step-by-step explanation:

A probability is the number of desired outcomes divided by the number of total outcomes.

In this problem:

For each jersey, there are 2+5+3 = 10 possible options, two of which are striped.

So twice 2/10

$p = (\frac{2}{10})^{2} = \frac{4}{100}$

4% probability that fazio selects a striped jersey both times.

5 0

3 years ago