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2 years ago

Mean of four numbers a ,b, c, and d is 8 and mean of seven

Mathematics

1 answer:

Nana76 [90]2 years ago

4 0

Answer:

17 1/3 or 17.33

Step-by-step explanation:

Mean of four numbers a, b, c, and d is 8:

(a + b + c + d)/4 = 8
⇒ a + b + c + d = 32

Mean of seven numbers x, y, z, a, b, c and d is 12:

(x + y + z + a + b + c + d)/7 = 12

Substitute the sum of 4 numbers:

x + y + z + 32 = 7*12
x + y + z = 84 - 32
x + y + z = 52

Mean of x, y and z is:

52/3 = 17 1/3 or 17.33

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Hi! I need help with the attached question in calc. Thank you:)

Elena L [17]

Answer:

3π square units.

Step-by-step explanation:

We can use the disk method.

Since we are revolving around AB, we have a vertical axis of revolution.

So, our representative rectangle will be horizontal.

R₁ is bounded by y = 9x.

So, x = y/9.

Our radius since our axis is AB will be 1 - x or 1 - y/9.

And we are integrating from y = 0 to y = 9.

By the disk method (for a vertical axis of revolution):

$\displaystyle V=\pi \int_a^b [R(y)]^2\, dy$

So:

$\displaystyle V=\pi\int_0^9\Big(1-\frac{y}{9}\Big)^2\, dy$

Simplify:

$\displaystyle V=\pi\int_0^9(1-\frac{2y}{9}+\frac{y^2}{81})\, dy$

Integrate:

$\displaystyle V=\pi\Big[y-\frac{1}{9}y^2+\frac{1}{243}y^3\Big|_0^9\Big]$

Evaluate (I ignored the 0):

$\displaystyle V=\pi[9-\frac{1}{9}(9)^2+\frac{1}{243}(9^3)]=3\pi$

The volume of the solid is 3π square units.

Note:

You can do this without calculus. Notice that R₁ revolved around AB is simply a right cone with radius 1 and height 9. Then by the volume for a cone formula:

$\displaystyle V=\frac{1}{3}\pi(1)^2(9)=3\pi$

We acquire the exact same answer.

8 0

2 years ago

Which of the following sets of angles sum to 180°? picture included, please help.

eduard

Answer:

Choice 3

Step-by-step explanation:

add 63 and 64 which gives you 127. Then you subtract 180 and 127. This gives you 53. 63+53+64=180. Know that the angle is 180 degrees too so you don't even have to do math.

8 0

3 years ago

Read 2 more answers

If three pounds of coffee costs $22.56, what is the cost of 1

NeX [460]

Answer:

$7.52 = 7 dollars and 52 cents.

Step-by-step explanation:

Given that three pounds of coffee = $22.56

1 pound of coffee = $22.56/3

Thus, we would have:

$\frac{22.56}{3} = 7.52$ .

A pound of coffee = $7.52

$7.52 = 7 dollars and 52 cents.

8 0

3 years ago

Gary has 23 quarters in his bank he saves 4 more quarters each week what will the total value of Gary’s bank be in four weeks??

geniusboy [140]

Answer:

Step-by-step explanation:

4 quarters x 4 weeks = 16 quarters

16 + 23= 39 quarters

8 0

3 years ago

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In last year, San Diego basketball team won 32 games, and lost 8 games. What percent of the games were won?

defon

Answer:

80%

Step-by-step explanation:

The total amount of games last year was 40.

32 + 8 = 40

question says the percent of games were won which means 32/40

In percentage, it means 80%

8 0

3 years ago