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hoa [83]
3 years ago
9

Darla spent $120.37 on groceries in January, $108.45 in February, and $114.86 in March. What was the average monthly cost of Dar

la’s groceries
Mathematics
1 answer:
kari74 [83]3 years ago
4 0
In order to find an average, you have to add all the numbers and divide by the number of things you added.

120.37 + 108.45 + 114.86 = 343.68
343.68/3 = 114.56

She spent an average of $114.56 each month on groceries.
You might be interested in
A snail can move 1/30 miles in 1/3 hour. How fast does a snail move in miles /hours
bekas [8.4K]

Answer:             1/10 miles/hour

To find how fast a snail moves in miles per hour, we can find the unit rate using a proportion.

<h2>Unit Rate</h2>

The unit rate is the amount per one unit. In this problem, the unit is for one hour. One way to find the unit rate is by using a proportion.

<h2>Proportions</h2>

Proportions look like two fractions set equal to each other with a missing variable to solve.

<h3>State our variables</h3>

let <em>x</em> be the number of miles per hour

<h3>Write a proportion</h3>

The first fraction has a number for the numerator (top) and denominator (bottom), because the question gives us the information. The second fraction has a missing value, <em>x</em>, that we are solving for. We can write <em>x</em> in the numerator.

\displaystyle{\frac{\frac{1}{30}\ mi}{\frac{1}{3}\ hr} = \frac{x\ mi}{1\ hr}}

<h2>Solve</h2>

We can solve by finding the scale factor. The scale factor is the number we can multiply the numerator by to find <em>x</em>.

<h3>Find the scale factor</h3>

Start with the proportion.

\displaystyle{\frac{\frac{1}{30}\ mi}{\frac{1}{3}\ hr} = \frac{x\ mi}{1\ hr}}

To find the scale factor,

  1. Take the denominator from the fraction with a variable: 1\ hr
  2. Take the denominator from the fraction that has no variable:  \frac{1}{3}\ hr
  3. Divide step 1 by step 2 and solve:  1\ hr\ \div\ \frac{1}{3}\ hr = 3

Our scale factor is <u>3</u>.

<h3>Solve for x</h3>

We can find <em>x</em> by multiplying the numerator in the first fraction by the scale factor. This is because <em>x</em> is also in the numerator.

\displaystyle{\frac{\frac{1}{30}\ mi}{\frac{1}{3}\ hr} = \frac{(\frac{1}{30}\ mi)*3}{1\ hr}}

\displaystyle{\frac{\frac{1}{30}\ mi}{\frac{1}{3}\ hr} = \frac{\frac{3}{30}\ mi}{1\ hr}}

Simplify 3/30 by dividing the fraction by 3.

\displaystyle{\frac{\frac{1}{30}\ mi}{\frac{1}{3}\ hr} = \frac{\frac{1}{10}\ mi}{1\ hr}}

x = 1/10

∴ a snail moves 1/10 miles per hour.

Learn another way to solve proportions here: brainly.com/question/18437927

7 0
2 years ago
Explain a real life situation where you may use trig ratios to find measure in right triangles.
OLEGan [10]
One example is if you wanted to measure the height of a tall building. You'll need to measure the distance from where you're standing to the base of the building. You'll also need the angle of elevation. To get the angle of elevation, start by looking completely horizontal, then tilt upward until your eyeline reaches the top of the building. Once you have those two things (the side and angle) you can use the tangent ratio to find the height. This is because

tan(angle) = opposite/adjacent

where in this case
angle = angle of elevation
opposite = height of building
adjacent = distance from your position to the base of the building

It takes a bit of algebra, but the opposite side can be solved for. You'll most likely need a calculator to compute the tangent ratio.

5 0
3 years ago
What??? What’s this?
Elis [28]
The answer is C because the statement would be if A is true then B is true. Hope this helps
4 0
3 years ago
Read 2 more answers
What is the solution to this equation?
Anettt [7]

Answer:

B. a = 5

Step-by-step explanation:

3(a - 4) + 1 = 9 - a

Distribute the 3 into the parenthesis.

3a - 12 + 1 = 9 - a

Add -12 and 1.

3a - 11 = 9 - a

Add a to both sides.

4a - 11 = 9

Add 11 to both sides.

4a = 20

Divide both sides by 4.

a = 5.

Proof:

3(a - 4) + 1 = 9 - a

Substitute variable.

3(5 - 4) + 1 = 9 - 5

Subtract inside parenthesis.

3(1) + 1 = 9 - 5

Multiply 3 and 1.

3 + 1 = 9 - 5

Add 3 and 1.

4 = 9 - 5

Subtract 5 from 9.

4 = 4.

6 0
3 years ago
At one point the average price of regular unleaded gasoline was ​$3.41 per gallon. Assume that the standard deviation price per
Aleonysh [2.5K]

Answer:

a)  1-\frac{1}{k^2} =1- \frac{1}{2^2}= 1-0.25 = 0.75

So we expected about 75% within two deviations from the mean

b) 1-\frac{1}{k^2} =1- \frac{1}{1.5^2}= 1-0.4444 = 0.556

So we expected about 55.6% within 1.5 deviations from the mean

And the limits are:

Lower = 3.41 -1.5*0.09 = 3.275

Upper = 3.41 +1.5*0.09 = 3.545

c) We can calculate how many deviations we are within the mean with the limits with this formula:

z =\frac{x-\mu}{\sigma}

And using the lower limit we got:

z = \frac{3.05-3.41}{0.09}=-4

And with the upper limit we got:

z = \frac{3.77-3.41}{0.09}=4

So then the value of k =4 and the percentage is given by:

1-\frac{1}{k^2} =1- \frac{1}{4^2}= 1-0.0625 = 0.9375

Step-by-step explanation:

Previous concepts and Data given  

\mu =3.41 reprsent the population mean

\sigma=0.09 represent the population standard deviation

The Chebyshev's Theorem states that for any dataset

• We have at least 75% of all the data within two deviations from the mean.

• We have at least 88.9% of all the data within three deviations from the mean.

• We have at least 93.8% of all the data within four deviations from the mean.

Or in general words "For any set of data (either population or sample) and for any constant k greater than 1, the proportion of the data that must lie within k standard deviations on either side of the mean is at least: 1-\frac{1}{k^2}

Part a

For this case we can find the percentage required replaincg k =2 and we got:

1-\frac{1}{k^2} =1- \frac{1}{2^2}= 1-0.25 = 0.75

So we expected about 75% within two deviations from the mean

Part b

For this case we can find the percentage required replaincg k =2 and we got:

1-\frac{1}{k^2} =1- \frac{1}{1.5^2}= 1-0.4444 = 0.556

So we expected about 55.6% within 1.5 deviations from the mean

And the limits are:

Lower = 3.41 -1.5*0.09 = 3.275

Upper = 3.41 +1.5*0.09 = 3.545

Part c

We can calculate how many deviations we are within the mean with the limits with this formula:

z =\frac{x-\mu}{\sigma}

And using the lower limit we got:

z = \frac{3.05-3.41}{0.09}=-4

And with the upper limit we got:

z = \frac{3.77-3.41}{0.09}=4

So then the value of k =4 and the percentage is given by:

1-\frac{1}{k^2} =1- \frac{1}{4^2}= 1-0.0625 = 0.9375

3 0
3 years ago
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