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3 years ago

Ella practice the piano for 2.4 hours each week about how many hours does she practice the piano each year

Mathematics

1 answer:

blondinia [14]3 years ago

3 0

There is ~ 52.15 weeks in a year.

Ella practices 2.4 hours each week

Multiply the two together

2.4 x 52.15 = 125.16

Ella practices ~125.16 hours each year.

hope this helps

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nasty-shy [4]

Answer:

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Step-by-step explanation:

7 0

3 years ago

Can someone please do a few of these problems for me

Anna007 [38]

Hey there! :)

The formula for finding volume of a cone : ( π · r² · h ) ÷ 3

Radius = 6
6² = 6 · 6 = 36

Height = 8

π = 3.14

Multiply:

8 × 6 × 3.14 = 150.72

The volume is 150.72 cubic meters

Hope this helps :)

6 0

3 years ago

What is the price elasticity of the demand for skateboards, when A shop owner wants to know what the effect would be of increasi

-BARSIC- [3]

Answer: The price elasticity of the demand for skateboards = 0.6.

Step-by-step explanation:

Since we have given that

Original price of skate boards = $200

Quantity of skate board = 10

New price of skate boards = $300

Quantity of skate board = 7

Since we know that "Price of commodity is inversely related to quantity demanded."

So, price elasticity of demand is given by

$e_d=\frac{\Delta q}{\Delta p}\times \frac{P}{Q}\\\\e_d=\frac{10-7}{300-200}\times \frac{200}{10}\\\\e_d=\frac{3}{100}\times 20\\\\e_d=\frac{3}{5}=0.6$

Hence, the price elasticity of the demand for skateboards = 0.6.

3 0

4 years ago

PLEASE HELP ME on #57 WITH ALL WORK SHOWN!!<br><br> Tmr is my exam pls help...

-Dominant- [34]

<h3>Answer: x = 1/2</h3>

=========================================================

Explanation:

Recall that quadratic form is ax^2+bx+c.

So we need an x^2 term followed by an x term, then a constant at the end.

It may not look it, but the given equation is nearly in quadratic form.

Rewrite 9^(2x) as (9^x)^2

We get this equivalent equation (9^x)^2 - 2*(9^x) - 3 = 0

From here, let's make w = 9^x. Replace every copy of '9^x' with 'w' and we end up with this new simpler equation: w^2 - 2w - 3 = 0

From here we can use the quadratic formula or factor. I'll factor.

w^2 - 2w - 3 = 0

(w - 3)(w + 1) = 0

w-3 = 0 or w+1 = 0

w = 3 or w = -1

---------------------

Now we use these values of w to find x

If w = 3, then,

w = 9^x

3 = 9^x

log(3) = log(9^x)

log(3) = x*log(9)

x = log(3)/log(9)

x = log(3)/log(3^2)

x = log(3)/(2*log(3))

x = 1/2

At the last step, we have the log(3) terms cancel.

Repeat for w = -1

w = 9^x

-1 = 9^x

log(-1) = log(9^x)

We run into a problem. The log of any negative number is not a real number output. In other words, 9^x is never negative. Raising any positive number to a real number output leads the result to be positive. Take a look at the graph of y = 9^x to confirm this.

In short, w = -1 is extraneous so it doesn't lead to any x value solution.

So only w = 3 is useful.

Ultimately, the only solution is x = 1/2.

3 0

3 years ago

The quality-control department of Starr Communications, the manufacturer of video-game cartridges, has determined from records t

notsponge [240]

Answer: (A) The probability that a cartridge purchased will have a video or audio defect is 1.9%

(B) The probability that a cartridge purchased will not have a video or audio defect is zero.

Step-by-step explanation: The data given shows that 1.2% (or 120) cartridges have video defects, 0.9% have audio defects (or 90) and 0.2% (or 20) have both audio and video defects.

The possible outcomes for all events (audio defects and video defects) is derived as 120 plus 90 which is equals 210 possibilities (or possible outcomes).

Therefore the probability of having an audio defect is calculated as follows;

P(Audio) = Number of required outcomes/Number of all possible outcomes

P(Audio) = 90/210

P(Audio) = 3/7

Also the probability of having a video defect is derived as follows;

P(Video) = Number of required outcomes/Number of all possible outcomes

P(Video) = 120/210

P(Video) = 4/7

However we should take note of the fact that 0.2% or 20 of the cartridges in the sample size has both audio and video defects. Hence the probability that a cartridge has both audio and video defects is calculated as;

P(Audio and Video) = Number of required outcomes/Number of all possible outcomes

P(Audio and Video) = 20/210

P(Audio and Video) = 2/21

To calculate the probability that a cartridge bought would have either an audio or a video defect would mean to add both probabilities together, but we MUST SUBTRACT the probability of having both an audio defect and video defect (that is P{Audio and Video}). The reason is that this is already included in both probabilities and we need to avoid double counting. Hence we have;

(A); P(Video OR Audio defect) = P(Audio) + P(Video) - P(Audio and Video)

P(Video OR Audio defect) = (3/7 + 4/7) - 2/21

P(Video OR Audio defect) = 1 - 2/21

P((Video OR Audio defect) = 19/21

Therefore the probability that a cartridge purchased will have a video or audio defect is 190, or better still 1.9%.

(B): From all possibilities shown, which is 210 possibilities of either events, we have determined that 120 will be the probability of having an audio defect and 90 will be the probability of having a video defect. Therefore the probability that a cartridge purchased will not fall into any of either possibilities is zero.

6 0

3 years ago