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3 years ago

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In Mrs. Diego’s class, 75% of all the students in the class participated in a clean up day. There are 32 students in the class.

How many students participated in the clean up day? A. 18 B. 20 C. 24 D. 28

2 answers:

oksano4ka [1.4K]3 years ago

5 0

Answer:

D.28

Step-by-step explanation:

OLEGan [10]3 years ago

3 0

The answer to this question is c 24.

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Samantha has $1,290 in a savings account that pays 4% simple interest. How much interest will she earn in 9 months? How much wil

Masja [62]

Given:

Principal = $1290

Rate of simple interest = 4%

Time = 9 months

To find:

The interest and total saving in the account altogether.

Solution:

The formula for simple interest is

$I=\dfrac{P\times r\times t}{100}$ ...(i)

where, P is principal, r is rate of interest and t is time in years.

We know that,

$12\ months=1\ year$

$1\ month=\dfrac{1}{12}\ year$

$9\ months=\dfrac{9}{12}\ year$

$9\ months=0.75\ year$

Putting P=1290, r=4 and t=0.75 in (i), we get

$I=\dfrac{1290\times 4\times 0.75}{100}$

$I=\dfrac{3870}{100}$

$I=38.70$

So, the simple interest is $38.70.

Total savings is

$1290+38.70=1328.70$

Therefore, the total amount in the account altogether is $1328.70.

4 0

3 years ago

The area of a square floor on a scale drawing is 25 square centimeters, and the scale drawing is 1 centimeter:4 ft. What is the

GREYUIT [131]

100 square feet 1:4 25:100

4 0

3 years ago

Prove or disprove that the circle with equation x^2-4x+y^2=-3 intersects the y axis

wel

The general equation given is x^2 - 4x + y^2 = -3. Transform this to an equation of a circle of the form x^2 + y^2 = r^2.

Use completing the square method:

x^2 - 4x + 4 + y^2 = -3 + 4
(x - 2)^2 + y^2 = 1

the center of the circle is (2,0) and r = 1

To check if it intersects the y axis, find the value of the x-intercept.

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3 years ago

Michela’s skateboard ramp is at an incline of 40°. When she attempts a trick on the ramp, she finds that it is too steep. She ad

marissa [1.9K]

Answer:

22.7604763 degrees

Step-by-step explanation:

Note that the answer is NOT 20 degrees.

She adjusted the ramp to half the original <em>incline</em>

Therefore we have tan 40 = x = 0.839099631.

We want an incline of y degrees where tan y = x/2 = 0.839099631/2 = 0.419549815

Taking the arctan of both sides, we get

y = arctan(0.419549815) = 22.7604763 degrees

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3 years ago

An Internet reaction time test asks subjects to click their mouse button as soon as a light flashes on the screen. The light is

Ganezh [65]

Answer:

(a) 0.20

(b) 31%

(c) 2.52 seconds

Step-by-step explanation:

The random variable <em>Y</em> models the amount of time the subject has to wait for the light to flash.

The density curve represents that of an Uniform distribution with parameters <em>a</em> = 1 and <em>b</em> = 5.

So, $Y\sim Unif(1,5)$

(a)

The area under the density curve is always 1.

The length is 5 units.

Compute the height as follows:

$\text{Area under the density curve}=\text{length}\times \text{height}$

$1=5\times\text{height}\\\\\text{height}=\frac{1}{5}\\\\\text{height}=0.20$

Thus, the height of the density curve is 0.20.

(b)

Compute the value of P (Y > 3.75) as follows:

$P(Y>3.75)=\int\limits^{5}_{3.75} {\frac{1}{b-a}} \, dy \\\\=\int\limits^{5}_{3.75} {\frac{1}{5-1}} \, dy\\\\=\frac{1}{4}\times [y]^{5}_{3.75}\\\\=\frac{5-3.75}{4}\\\\=0.3125\\\\\approx 0.31$

Thus, the light will flash more than 3.75 seconds after the subject clicks "Start" 31% of the times.

(c)

Compute the 38th percentile as follows:

$P(Y$

Thus, the 38th percentile is 2.52 seconds.

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3 years ago