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icang [17]
2 years ago
7

Elvira was trying to find out the number of students in the courtyard during lunch. She doesn’t remember how many students were

there to start, but knows how many students there were at the end of the lunch period. These are her observations: · The original students were joined by four more students. · Those students were each joined by 2 students, multiplying the students by 3. · Half the students left. If there were 15 students at the end of the lunch period, which equation would help Elvira find how many students were in the courtyard at the beginning of lunch?
SOMEONE, ANYONE PLEASE HELP ME WITH THIS QUESTION :(
ANYONE CAN HELP IF THEY WANT, PLEASE!!!!
Mathematics
1 answer:
il63 [147K]2 years ago
4 0

Answer:

2x3=6+9=15?

Step-by-step explanation:

Im sorry if i didnt help.

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A biker moves 2.5 times faster than a walker. They started moving simultaneously in the same direction from the same point. In t
saveliy_v [14]

Answer:

The speed of the biker is 15

Step-by-step explanation:

First, you call the speed of the walker x, and the speed of the biker 2.5x.

Then you know that speed times time equals distance, so you set up and equation. You do x times 2, which is 2x, and then 2.5x times 2, which is 5x. Then, since the distance between them is 18 miles, the equation would be 5x-2x=18. You would get 3x=18, and x is 6. So 6 is the speed of the walker, and 6 times 2.5 = 15, so the speed of the biker is 15.


5 0
3 years ago
Read 2 more answers
Suppose that the mean time that visitors stay at a museum is 94.2 minutes with a standard deviation of 15.5 minutes. The standar
Maurinko [17]

Answer:

94.2 -0.994*3.1 = 91.1186

94.2 +0.994*3.1 = 97.2814

And the 68% confidence interval is given by (91.1186, 97.2814)

Step-by-step explanation:

For this case we know that mean time that visitors stay at a museum is given by:

\bar X = 94.2

The standard deviation is given by:

s= 15.5

And the standard error is given by:

SE = \frac{s}{\sqrt{n}} =3.1

And we want to interval captures 68% of the means for random samples of 25 scores and for this case the critical value can be founded like this using the normal standard distribution or excel:

z_{\alpha/2}= \pm 0.994

We can find the interval like this:

\bar X \pm ME

And replacing we got:

94.2 -0.994*3.1 = 91.1186

94.2 +0.994*3.1 = 97.2814

And the 68% confidence interval is given by (91.1186, 97.2814)

7 0
3 years ago
I will mark brainliest if ur answer is correct
sergeinik [125]

Answer:

43°

Step-by-step explanation:

80°-37°= 43°

3 0
3 years ago
Read 2 more answers
What is the value of x?
andrew11 [14]
Hope this will help you .

answer is 68

given than 2 sides are equal therefor 2 angles are also equal ,

so, angle 1 + angle2 + angleX = 180 [ASP]

2angle1 + angle X = 180
angle x = 150 - [56][2]
angle x = 180-112

ANGLE x = 68 DEGREE
MARK IT BRAINIEST IF IT WAS REALLY HELPFUL.
4 0
3 years ago
Cot^2x csc^2x + 2 csc^2x –cot^2 = 2
kow [346]

Answer:

x = π/2 + πk

Step-by-step explanation:

cot² x csc² x + 2 csc² x − cot² x = 2

Multiply both sides by sin² x:

cot² x + 2 − cos² x = 2 sin² x

Add cos² x to both sides:

cot² x + 2 = 2 sin² x + cos² x

Pythagorean identity:

cot² x + 2 = sin² x + 1

Subtract 1 from both sides:

cot² x + 1 = sin² x

Pythagorean identity:

csc² x = sin² x

Multiply both sides by sin² x:

1 = sin⁴ x

Take the fourth root:

sin x = ±1

Solve for x:

x = π/2 + 2πk, 3π/2 + 2πk

Which simplifies to:

x = π/2 + πk

4 0
3 years ago
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