<img src="https://tex.z-dn.net/?f=%20" id="TexFormula1" title=" " alt=" " align="absmiddle" class="latex-formula"><br><img src="

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3 years ago

https://tex.z-dn.net/?f=%20-%203%20%7Bx%7D%20%2B%207" id="TexFormula2" title=" - 3 {x} + 7" alt=" - 3 {x} + 7" align="absmiddle" class="latex-formula">

Mathematics

1 answer:

seropon [69]3 years ago

6 0

$\text{The range of}\ y=-3^x\ \text{is}\ (-\infty;\ 0).\\\\\text{The range of}\ f(x)=-3^x+7\ \text{is}\ (-\infty;\ 7)$

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A woman saw oranges and mangos ad the market. She bought some oranges at 35 cents each and some mangoes at $1.00. if she bought

marysya [2.9K]

Answer: 20 oranges and 5 mangoes

Step-by-step explanation:

Define the following:

x = number of oranges

y = number of mangoes

Make the following system of equations:

x + y = 25

0.35x + 1.00y = 12.00

Solve for x:

y = 25 - x

⇒ 0.35x + 1.00(25 - x) = 12.00

⇒ 0.35x + 25 - x = 12.00

⇒ -0.65x = -13.00

⇒ x = 20

Solve for y:

20 + y = 25

y = 5

∴ 20 oranges and 5 mangoes were purchased.

8 0

1 year ago

What is the estimate of 979

saw5 [17]

I'm pretty sure that it would be 1,000...

4 0

3 years ago

Risk taking is an important part of investing. In order to make suitable investment decisions on behalf of their customers, port

GrogVix [38]

Answer:

$a=49.5 -1.28*15=30.3$

So the value of height that separates the bottom 10% of data from the top 90% is 30.3.

If the score is lower than 30.3 we consider this score as risk averse

Step-by-step explanation:

Previous concepts

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".

Solution to the problem

Let X the random variable that represent the scores of a population, and for this case we know the distribution for X is given by:

$X \sim N(49.5,15)$

Where $\mu=49.5$ and $\sigma=15$

We are interested in the bottom 10% of the data.

For this part we want to find a value a, such that we satisfy this condition:

$P(X>a)=0.9$ (a)

$P(X$ (b)

Both conditions are equivalent on this case. We can use the z score again in order to find the value a.

As we can see on the figure attached the z value that satisfy the condition with 0.1 of the area on the left and 0.9 of the area on the right it's z=-1.28. On this case P(Z<-1.28)=0.1 and P(z>-1.28)=0.9

If we use condition (b) from previous we have this:

$P(X$