7

An urn contains 3 red and 7 black balls. Players A and B take turns (A goes first) withdrawing balls from the urn consecutively.

andrey2020 [161]

Answer:

The probability that A selects the first red ball is 0.5833.

Step-by-step explanation:

Given : An urn contains 3 red and 7 black balls. Players A and B take turns (A goes first) withdrawing balls from the urn consecutively.

To find : What is the probability that A selects the first red ball?

Solution :

A wins if the first red ball is drawn 1st,3rd,5th or 7th.

A red ball drawn first, there are $E(1)= ^9C_2$ places in which the other 2 red balls can be placed.

A red ball drawn third, there are $E(3)= ^7C_2$ places in which the other 2 red balls can be placed.

A red ball drawn fifth, there are $E(5)= ^5C_2$ places in which the other 2 red balls can be placed.

A red ball drawn seventh, there are $E(7)= ^3C_2$ places in which the other 2 red balls can be placed.

The total number of total event is $S= ^{10}C_3$

The probability that A selects the first red ball is

$P(A \text{wins})=\frac{(^9C_2)+(^7C_2)+(^5C_2)+(^3C_2)}{^{10}C_3}$

$P(A \text{wins})=\frac{36+21+10+3}{120}$

$P(A \text{wins})=\frac{70}{120}$

$P(A \text{wins})=0.5833$

6 0

3 years ago

Integrate G(x,y,z)equalsz over the parabolic cylinder yequalszsquared, 0less than or equalsxless than or equals2, 0less than

yKpoI14uk [10]

I gather you're supposed to compute the integral of $G(x,y,z)=z$ over a surface $S$ that is the part of the parabolic cylinder $y=z^2$ with $0\le x\le2$ and $0\le z\le\frac{\sqrt{15}}2$ .

We can parameterize $S$ by

$\vec s(x,z)=x\,\vec\imath+z^2\,\vec\jmath+z\,\vec k$

with the given constraints on $x$ and $z$ . Take the normal vector to $S$ to be

$\vec s_x\times\vec s_z=-\vec\jmath+2z\,\vec k$

so that the surface element is

$\mathrm dS=\|\vec s_x\times\vec s_z\|\,\mathrm dx\,\mathrm dz=\sqrt{1+4z^2}\,\mathrm dx\,\mathrm dz$

Then in the integral, we have

$\displaystyle\iint_Sz\,\mathrm dS=\int_0^2\int_0^{\sqrt{15}/2}z\sqrt{1+4z^2}\,\mathrm dz\,\mathrm dx=\boxed{\frac{21}2}$

5 0

3 years ago

The sum of two numbers is twenty-four. The difference of the two numbers is four.

RSB [31]

Answer:

$x + y = 24$

$x - y = 4$

Now, add these two equations.

You get,

$2x = 28$

$x = \frac{28}{2}$

$x = 14$

Given,

$x + y = 24$

$14 + y = 24$

$y = 24 - 14$

$y = 10$

You can test this to the other equation as well.

$x - y = 4$

$14 - 10 = 4$

Hence, the two numbers are 14 and 10.

3 0

2 years ago

The scale factor from a small triangle ABC to a large triangle XYZ is 5. How many times larger will the perimeter of triangle XY

Ierofanga [76]

Answer:

Answer below :)

Step-by-step explanation:

Hi there!

Question 4 - the answer will be 5. Since the scale factor is 5, we would (hypothetically) multiply the area by 5 to get the new area of XYZ, so area XYZ is 5 times the area of ABC.

Question 5 - A.

First we multiply 45 by 12 to find the amount in inches. This is 540. Now, we divide that by 6 to get 90. This is our scale factor in inches, but the answers only show the scale in feet, so we have to convert. Divide 90 by 12 to get 7.5.

I hope this helps!

4 0

2 years ago

When 118 Is divided by 118 by 11 with one is quotient and remainder

andrezito [222]

Answer:

Step-by-step explanation:

Divide two numbers, a dividend and a divisor, and find the answer as a quotient with a remainder. Learn how to solve long division with remainders, or practice your own long division problems and use this calculator to check your answers.Long division with remainders is one of two methods of doing long division by hand. It is somewhat easier than solving a division problem by finding a quotient answer with a decimal.

3 0

3 years ago