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3 years ago

15

Nina babysits on weekends for extra money. The function f(t) is equal to how much money she earns after babysitting t hours. On

Friday night, f(4)=60. How many hours did Nina babysit on Friday night?

2 answers:

Darina [25.2K]3 years ago

6 0

Answer:

4

Step-by-step explanation:

t is replaced by 4 and t = hours

Dmitry_Shevchenko [17]3 years ago

6 0

Answer:4=t

Step-by-step explanation:

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Describe how to use a ten fact to find the difference for fifteen take away eight

sertanlavr [38]

15 - 8

8 + 2 is 10, so there are 5 leftover. 2 + 5 is 7, so 8 + 7 is 15.

6 0

3 years ago

If Kevin wants a 90 average in math after 5 tests and his first 4 tests are 76, 92, 89 and 97 what does he need on the fifth tes

Keith_Richards [23]

You need to understand that you're solving for the average, which you already know: 90. Since you know the values of the first three exams, and you know what your final value needs to be, just set up the problem like you would any time you're averaging something.
Solving for the average is simple:
Add up all of the exam scores and divide that number by the number of exams you took.
(87 + 88 + 92) / 3 = your average if you didn't count that fourth exam.
Since you know you have that fourth exam, just substitute it into the total value as an unknown, X:
(87 + 88 + 92 + X) / 4 = 90
Now you need to solve for X, the unknown:
87
+
88
+
92
+
X
4
(4) = 90 (4)
Multiplying for four on each side cancels out the fraction.
So now you have:
87 + 88 + 92 + X = 360
This can be simplified as:
267 + X = 360
Negating the 267 on each side will isolate the X value, and give you your final answer:
X = 93
Now that you have an answer, ask yourself, "does it make sense?"
I say that it does, because there were two tests that were below average, and one that was just slightly above average. So, it makes sense that you'd want to have a higher-ish test score on the fourth exam.

4 0

3 years ago

Read 2 more answers

I need help finding the slope

Scilla [17]

Answer:

The answer is ✰ 4 ✰

Step-by-step explanation:

:))

8 0

2 years ago

Ashley, Bob, Claire, and Daniel are among 13 students who entered a lottery to win a free vacation to Paris.

AlladinOne [14]

Answer:

0.0014 = 0.14% probability that Ashley, Bob, Claire, and Daniel will be chosen.

Step-by-step explanation:

A probability is the number of desired outcomes divided by the number of total outcomes.

The order in which the students are chosen is not important, so the combinations formula is used to solve this question.

Combinations formula:

$C_{n,x}$ is the number of different combinations of x objects from a set of n elements, given by the following formula.

$C_{n,x} = \frac{n!}{x!(n-x)!}$

Desired outcomes:

4 students from a set of 4(Ashley, Bob, Claire, and Daniel). So

$D = C_{4,4} = \frac{4!}{4!(4-4)!} = 1$

Total outcomes:

4 students from a set of 13(number of students in the lottery). So

$T = C_{13,4} = \frac{13!}{4!(13-4)!} = 715$

Probability:

$p = \frac{D}{T} = \frac{1}{715} = 0.0014$

0.0014 = 0.14% probability that Ashley, Bob, Claire, and Daniel will be chosen.

7 0

3 years ago

Thirty three different video games showing violence were observed. The duration times of violence (in seconds) were recorded. W

AlladinOne [14]

Answer:

The "df" stands for "degrees of freedom", and represents the number of independent observations in a set of data.

Its value in this case is df=32.

Step-by-step explanation:

The sample is of size n=33.

As we do not know the population's standard deviation, we use as estimate the sample's standard deviation. Because of this, we use the t-statistic in place of the z-value.

The "df" stands for "degrees of freedom", and represents the number of independent observations in a set of data (the data in this case is the sample of 33 video games).

In one-sample tests, the degrees of freedom are calculated as:

$df=N-1=33-1=32$

6 0

3 years ago