What is the value of x in the equation 3x-4y=65, when y=4?

There are 9 students in a class: 2 boys and 7 girls. If the teacher picks a group of 4 at random, what is the probability that e

notsponge [240]

Answer:

<h2>28% probability that every student in the group is a girl.</h2>

Step-by-step explanation:

In this problem we have independent events, that is, the event "picking a girl" doesn't affect an "picking a boy", also, picking picking a girl doesn't affect the probability of the other subjects.

So, the probability when the first girl is being picked is:

$P_{1}=\frac{7 \ girls}{9 \ students}$

Because among the total 9 students, there are 7 girls.

Now, after picking one girl, there remains 6 girls and 8 students to be picked. So, the probability of the second girl would be:

$P_{2}=\frac{6 \ girls}{8 \ students}$

Then, the probability of the third girl:

$P_{3}=\frac{5 \ girls}{7 \ students}$

The fourth girl probability:

$P_{3}=\frac{4 \ girls}{6 \ students}$

Therefore, the probability of picking all 4 girls would be the product of each probability, because events are independent (we use product when they are independent):

$P=\frac{7 \ girls}{9 \ students} \times \frac{6 \ girls}{8 \ students} \times \frac{5 \ girls}{7 \ students} \times \frac{4 \ girls}{6 \ students}\\P=\frac{5}{18}=0.28 \ (or \ 28\%)$

Therefore, there's 28% probability that every student in the group is a girl.

5 0

2 years ago

Can someone see if this is right

iren [92.7K]

Correct, the answer is B.

5 0

3 years ago

Read 2 more answers

1. A submarine is 40 meters below sea level. It goes up 12 meters, then goes down 30 meters. What is the submarine's new positio

Lilit [14]

Answer:

Question Number 1: C. -58 meters

Question Number 2: 1.45 lbs

Step-by-step explanation:

Question Number 1:

40 - 12 = 28 meters below sea level

28 + 30 = 58 meters below sea level . So respectively its negative, so -58 would be your answer .

Question Number 2:

To figure out how many pounds of carrots are in each cake, divided 7.25 by 5. That equals 1.45. So one cake needs 1.45 pounds of carrots.

8 0

2 years ago

A vendor prepares 100.00 hotdogs every day and sells at $20.00/piece. For each hot dog, he spends $12.00 in the raw material. Ad

astra-53 [7]

Answer:

$397.34 (if he sold the 20 leftover hot dogs), $297.34 if he didn't.

Step-by-step explanation:

We are going to assume that a month has 30 days.

First, we are going to see how much money the vendor got from selling the 80 hot dogs. He sold 80 hot dogs at 20 dollars/piece = 1600 dollars.

We need to subtract the amount of money he spent in each hot dog (12 dollars in raw material plus one dollar for packing): 13 dollars x 100 hot dogs he prepared = 1300 dollars

He also spends a total of 80 dollars per month in truck rent, electricity and other expenses. If we divide this by the amount of days per month we have: 80/30 = 2.66

The problem doesn't tell us that there were unhappy customers that day so that amount is zero.

We are going to assume that the vendor sold the remaining 20 hot dogs at 5 dollars/piece. 20 x 5 = 100.

Thus, the profit for that day is:

1600 - 1300 - 2.66 + 100 = 397.34

(Note: If the vendor did not sell the leftover hot dogs and he actually only sold 80 hot dogs, then the profit would be: 1600 - 1300 - 2.66 = 297.34)

6 0

2 years ago

Suppose an automobile manufacturer designed a radically new lightweight engine and wants to recommend the grade of gasoline that

Deffense [45]

Answer:

The F-statistic used to test the hypothesis that the miles per gallon for each fuel are the same is 4.07.

Step-by-step explanation:

There are four treatments in the data given, i.e. k = 4.

Total number of observations, n = 12.

Note: degrees of freedom is denoted as df.

For treatment, the degrees of freedom = k-1 = 4-1 =3 df.

The total degrees of freedom = n-1 = 12-1 = 11 df.

The error in degrees of freedom = df (total) - df(treatment)

The error in degrees of freedom = 11 - 3 = 8 df

At α = 0.05 level,from the F table, the F-statistic with (3 , 8)df is 4.07.

Therefore, the F-statistic used to test the hypothesis that the miles per gallon for each fuel are the same is 4.07.

8 0

2 years ago