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1 year ago

How long is a distance of 8 km if measured on a map with a scale of 1:50,000

1 answer:

6 0

Since this is a ratios and proportions problem, you would set up the equation like this:
1/50,000 = x/8 x is the length of the distance on the map

After that, you cross multiply and you will get 50,000x=8
You then solve for x to get 0.00016

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A collection of quarters and nickels contains at least 42 coins and is worth at most $8.00. If the collection contains 25 quarte

Elenna [48]

Answer:

Step-by-step explanation:

9 0

1 year ago

Read 2 more answers

I also need help with this problem.

nadezda [96]

We will use substitution to solve this system of linear equations, as the first equation has x and y with no coefficients, which makes it easier to find one in terms of the other. We can then substitute that value in the other equation and find the values of x and y.

x = y + 5 ---> equation 1

3x + 2y = 5 ---> equation 2

From equation 1, we get the value of x as y + 5. Using the substitution method, we can find the value of y by substituting (y+5) for x in the 2nd equation.

3(y+5) + 2y = 5

3y + 15 + 2y = 5

5y = 5 - 15

5y = -10

y = -2

Subsituting this value of y in (y+5), we can find x.

x = y + 5

x = -2 + 5

x = 3

Therefore, x = 3 and y = -2.

I will also solve this using elimination method.

Let us multiply equation 1 by 2, so that we get 2y in both equations.

2x = 2y + 10

3x + 2y = 5

Let us add both the equations.

2x + 3x + 2y = 5 + 2y + 10

5x = 15 + 2y - 2y

5x = 15

x = 3

Substituting this value of x in equation 1, we get

x = y + 5

3 = y + 5

y = 3 - 5

y = -2

Therefore, x = 3 and y = -2.

7 0

1 year ago

The extract of a plant native to Taiwan has been tested as a possible treatment for Leukemia. One of the chemical compounds prod

True [87]

Answer:

a) 57.35%

b) 99.99%

c) 68.27%

Step-by-step explanation:

When we have a random variable X that is normally distributed with mean $\large\bf \mu$ and standard deviation $\large\bf \sigma$ , then

The probability that the random variable has a value less than a, P(X < a) = P(X ≤ a) is the area under the normal curve with mean $\large\bf \mu$ and standard deviation $\large\bf \sigma$ to the left of a.

The probability that the random variable has a value greater than b, P(X > b) = P(X ≥ b) is the area under the normal curve with mean $\large\bf \mu$ and standard deviation $\large\bf \sigma$ to the right of b.

The probability that the random variable has a value between a and b, P(a < X < b) = P(a ≤ X ≤ b) = P(a < X ≤ b)= P(a ≤ X < b) is the area under the normal curve with mean $\large\bf \mu$ and standard deviation $\large\bf \sigma$ between a and b.

In this case, the random variable is the collagen amount found in the extract of the plant. The mean is 63 g/ml and the standard deviation is 5.4 g/ml

(a) What is the probability that the amount of collagen is greater than 62 grams per mililiter?

As we have seen, we need to find the area under the normal curve with mean 63 and standard deviation 5.4 to the right of 62 (see picture).

You can find this value easily with a calculator or a spreadsheet. If you prefer the old-style, then you have to standardize the values and look up in a table.

If you have access to Excel or OpenOffice Calc, you can find this value by introducing the formula:

1- NORMDIST(62,63,5.4,1) in Excel

1 - NORMDIST(62;63;5.4;1) in OpenOffice Calc

and we will get a value of 0.5735 or 57.35%

(b) What is the probability that the amount of collagen is less than 90 grams per mililiter?

Now we want the area to the left of 90

NORMDIST(90,63,5.4,1) in Excel

NORMDIST(90;63;5.4;1) in OpenOffice Calc

You will get a value of 0.9999 or 99.99%

(c) What percentage of compounds formed from the extract of this plant fall within 1 standard deviations of the mean?

You can use either the rule that 68.27% of the data falls between $\large\bf \mu -\sigma$ and $\large\bf \mu +\sigma$ or compute area between 63 - 5.4 and 63 + 5.4, that is to say, the area between 57.6 and 68.4

In Excel

NORMDIST(68.4,63,5.4,1) - NORMDIST(57.6,63,5.4,1)

In OpenOffice Calc

NORMDIST(68.4;63;5.4;1) - NORMDIST(57.6;63;5.4;1)

In any case we get a value of 0.6827 or 68.27%

3 0

1 year ago

Kenny types 280 words. How long did he type for? A.4 B. 5 C.6 D. 7

zlopas [31]

Are you sure you didn’t miss anything while writing the question?

Cause we have nothing to go off. Everybody types differently so there is no way for us to say how long he typed for, unless we were given aprox how many words he wrote in a minute or something

5 0

1 year ago

Read 2 more answers

Simplify 4a^3b^2 x 3a*6b^5

Strike441 [17]

Answer:

Step-by-step explanation:

(4a³b² )* (3a⁶b⁵) = 4*3 *a⁽³⁺⁶⁾ * b⁽²⁺⁵⁾

= 12a⁹b⁷

4 0

1 year ago