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BlackZzzverrR [31]

4 years ago

9

A student has $78 in his checking account. If the student spends $12 on lunch, which number could be combined with the amount le

ft in the account to make zero?

2 answers:

Alborosie4 years ago

7 0

Answer:

-66

Step-by-step explanation:

There will be $66 left after the $12 spent on lunch. 66 + -66 = 0

tester [92]4 years ago

7 0

Answer:

-66 (Option C)

Step-by-step explanation:

78-12=66-66=0

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The length of a football playing field is 100 yards between the opposing goal lines. What is the length of the football field in

sweet-ann [11.9K]

Answer:

33.3

Step-by-step explanation:

100 divided by 3

3 0

3 years ago

1. Contaminated water is subjected to a cleaning process. The concentration of the

Leokris [45]

Answer:

The concentration of pollutants in the water can be defined as the quotient between the mass of pollutants and the total mass of water.

Assuming that 1L of water weighs 1000 grams, we know that:

Mass of pollutants = 5mg = 0.005g.

Initial concentration = 0.005g/1000g = 0.000005

If we multiply this by 100%, we get the percentage:

0.000005*100% = 0.0005%

Now, the mass of pollutants decreases by 10% each hour.

So if initially, we have 5mg

After one hour, we will have: 5mg - 0.1*5mg = 5mg*(0.9).

After another hour, we will have: 5mg*(0.9) - 0.1*5mg*0.9 = 5mg*(0.9)^2.

And so on, then after n hours, the mass of pollutants will be:

M(n) = 5mg*(0.9)^n

Or we can write this in grams as:

M(n) = 0.005g*(0.9)^n

Then the concentration as a function of time in hours will be:

C(n) = M(n)/1000g = (0.005g/1000g)*(0.9)^n

Notice that the thing between the parentheses is the initial concentration, then if we write this in percentage form:

c(n) = 100%*(0.005g/1000g)*(0.9)^n = 0.0005%*(0.9)

The function that represents the concentration of polution in the water as a function of hours is:

c(n) = 0.0005%*(0.9)

6 0

3 years ago

Classify each figure on the triangle

ipn [44]

All the triangles are isosceles meaning that they have to sides that are equal

5 0

3 years ago

Read 2 more answers

Consider a value to be significantly low if its z score less than or equal to minus−2 or consider a value to be significantly hi

ziro4ka [17]

Answer:

If the weight is higher than 5.8886 gr would be considered significantly high

If the weight is lower than 5.6121 gr would be considered significantly low

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 weights of a population, and for this case we know the distribution for X is given by:

$X \sim N(5.75241,0.06281)$

Where $\mu=5.75241$ and $\sigma=0.06281$

And the best way to solve this problem is using the normal standard distribution and the z score given by:

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

For the case when z =-2 we can do this:

$-2 = \frac{X-5.75241}{0.06281}$

And if we solve for X we got:

$X = 5.75241 -2*0.06281 =5.6121$

And for the other case when Z=2 we have:

$2 = \frac{X-5.75241}{0.06281}$

And if we solve for X we got:

$X = 5.75241 +2*0.06281 =5.8886$

If the weight is higher than 5.8886 gr would be considered significantly high

If the weight is lower than 5.6121 gr would be considered significantly low

5 0

3 years ago

PLEASE ANSWER Chelsea is budgeting for her trip to the mall. She does not want to spend any more than $140. If she wants to buy

Tcecarenko [31]

Let s equal the number of shirts she can buy

140 > $28.50 + $20.75s
111.50 > 20.75s
5.37 > s

so we round down. she can buy 5 shirts, plus the one dress and she would spend less than $140

4 0

3 years ago