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2 years ago

If a person rows to his favorite fishing spot 21 miles downstream in the same amount of time that he rows 7 miles

Mathematics

1 answer:

klio [65]2 years ago

8 0

28 miles upstream requires 28/7 = 4 hours.

28 miles downstream requires 28/21 = 4/3 hours, or 1 hour and 20 minutes.

How long does it take him to cover 28 miles?

Apply the distance formula:

d = rt

where

d is distance

r is rate or speed

t is time

21 = t*(r+7) = rt+ 7t

7 = t *(r-7) = rt - 7t

28 = 2rt

14 = rt

21 = rt + 7t

21 = 14 + 7t

7 = 7t

t=1

21 = (r+7)*1 = r+7

r = 14

The speed of the boat is 14 mph. With the current (downstream), the speed is 14+7 = 21 mph, so 21 miles are traveled in 1 hour. Against the current (upstream), the speed is 14-7 = 7 mph, which means 7 miles are traveled in the same 1-hour time frame.

28 miles downstream requires 28/21 = 4/3 hours, or 1 hour and 20 minutes.

28 miles upstream requires 28/7 = 4 hours.

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Answer:

Step-by-step explanation:

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Answer:

a. The mean of the sample is M=35.

The variance of the sample is s^2=39.125.

The standard deviation of the sample is s=6.255.

b. z=-1.6

c. SEM = 2.212

Step-by-step explanation:

The mean of the sample is M=35.

The variance of the sample is s^2=39.125.

The standard deviation of the sample is s=6.255.

Sample mean

$M=\dfrac{1}{8}\sum_{i=1}^{8}(27+25+32+40+43+37+35+38)\\\\\\ M=\dfrac{277}{8}=35$

Sample variance and standard deviation

$s^2=\dfrac{1}{(n-1)}\sum_{i=1}^{8}(x_i-M)^2\\\\\\s^2=\dfrac{1}{7}\cdot [(27-(35))^2+(25-(35))^2+(32-(35))^2+(40-(35))^2+(43-(35))^2+(37-(35))^2+(35-(35))^2+(38-(35))^2]\\\\\\$

$s^2=\dfrac{1}{7}\cdot [(58.141)+(92.641)+(6.891)+(28.891)+(70.141)+(5.64)+(0.14)+(11.39)]\\\\\ s^2=\dfrac{273.875}{7}=39.125\\\\\\s=\sqrt{39.125}=6.255$

b. If the population mean is 45, the z-score for M=35 would be:

$z=\dfrac{M-\mu}{\sigma}=\dfrac{35-45}{6.255}=\dfrac{-10}{6.255}=-1.6$

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3 years ago

Use the Midpoint Rule with the given value of n to approximate the integral. Round the answer to four decimal places. 3 sin(x2)

sweet [91]

The value of the given statement according to the mid point theorem is 5.

According to the statement

we have given that the equation and we have to integrate it with the help of the mid point theorem.

So, For this purpose, we know that the

The midpoint theorem states that “The line segment in a triangle joining the midpoint of two sides of the triangle is said to be parallel to its third side and is also half of the length of the third side.”

So, The given equation is

$\int\limits^6_0 {Sinx } \, dx$

where n = 4

And

The mid point formula is a with limits a to b is

f(x) dx ≈ Δx (f (x₀ + x₁)/2) + (f (x₁ + x₂)/2) + ... (f (xₓ₋₂ + xₓ₋₁)/2) + (f (xₓ₋₁ + x)/2))

Then

Where Δx = (b-a)/n

Recall that

a= 0

b= 64 and

n=4, therefore,

Δx = (64-0)/4 = 16

The next step requires that the interval [0,64] be divided into 4 sub-intervals with length = Δx =16

Hence, we've got, 0, 16, 32, 48, 64.

From this point, we calibrate the respective functions as follows:

f (x₀ + x₁)/2) = f ((0+16)/2) = f(8) = Sin (8) = 0.98935824662

(f (x₁ + x₂)/2) = f((16+32)/2) = f(24) =Sin (24) = -0.905578362

(f (x₂ + x₃)/2) = f((32+48)/2) = f(40) = Sin (40) = 0.74511316047

(f (x₃ + x₄)/2) = f((48+64)/2) = f(56) = Sin (56) = -0.52155100208

At this point, we sum up the above values derive the product of the total and Δx = 16

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= 16 (0.30734204301)

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1 year ago

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Answer:

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Step-by-step explanation:

From the question we are told that

the given equation is

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This given equation can be represented as

$\= r (t) = [4 -3t , -5+t,3-t]$

Generally this equation can be represented in terms of the parametric equations as follows

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