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2 years ago

Please help! I’ll give brainliest to whoever is right!

Mathematics

1 answer:

masya89 [10]2 years ago

5 0

sample Y is 98%

sample Z is 95.8%

;)

brain;iest

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I’m helpless please help me

nignag [31]

Answer: I think the last one sorry of I am wrong

Step-by-step explanation:

7 0

2 years ago

A motorboat travels 244 kilometers in 4 hours going upstream and 749 kilometers in 7 hours going downstream. What is the rate of

Kryger [21]

Answer:

Speed of Motorboat = 84 kmph

Speed of Current = 23 kmph

Step-by-step explanation:

Distance Equation is:

D = RT

Where

D is distance

R is rate

T is time

Downstream rate is rate of boat PLUS current

Upstream rate is rate of boat MINUS current

Let rate of boat be "x" and rate of current be "c".

From first statement, we can write:

244 = (x - c)(4)

From second statement, we can write:

749 = (x + c)(7)

The first equation becomes:

244 = 4x - 4c

The second equation becomes:

749 = 7x + 7c

Multiplying first equation by 7 , we have:

7 * [244 = 4x - 4c] = 1708 = 28x - 28c

Multiplying 2nd equation by 4, we have:

4 * [749 = 7x + 7c] = 2996 = 28x + 28c

Now we add up these equations (in bold):

1708 = 28x - 28c

2996 = 28x + 28c

----------------------------

4704 = 56x

x = 4704/56

x = 84

Now using this value and plugging in original equation, we can find "c":

244 = 4x - 4c

244 = 4(84) - 4c

244 = 336 - 4c

4c = 92

c = 92/4

c = 23

<u>Speed of Motorboat = 84 kmph</u>

<u>Speed of Current = 23 kmph</u>

6 0

3 years ago

Make v the subject of the formula in H=m(v²-u²)/2gx

goldfiish [28.3K]

Answer:

$v=\sqrt{\dfrac{H\times 2gx}{m}+u^2}$

Step-by-step explanation:

The given formula is :

$H=\dfrac{m(v^2-u^2)}{2gx}$

We need to find the formula for v.

Cross multiplying the given formula.

$H\times 2gx=m(v^2-u^2)$

Dividing both sides by m. So,

$\dfrac{H\times 2gx}{m}=\dfrac{m(v^2-u^2)}{m}\\\\(v^2-u^2)=\dfrac{H\times 2gx}{m}$

Adding both sides by u².

$(v^2-u^2)+u^2=\dfrac{H\times 2gx}{m}+u^2\\\\v^2=\dfrac{H\times 2gx}{m}+u^2\\\\\text{So},\\\\v=\sqrt{\dfrac{H\times 2gx}{m}+u^2}$

Hence, this is the required formula.

4 0

2 years ago

Imagine using two of these triangles to construct a figure. What are the characteristics of the figure? Select all that apply. I

Rasek [7]

Answer:

A, B, D, E :)

Step-by-step explanation:

4 0

2 years ago

Read 2 more answers

Let $r$ and $s$ be the roots of $3x^2 + 4x - 12 = 0.$ Find $r^2 + s^2.$

Paul [167]

We can factorize the quadratic as

$3x^2 + 4x - 12 = 3 (x - r) (x - s)$

and expand the right side to get

$3x^2 + 4x - 12 = 3x^2 - 3(r + s) x + 3rs$

$\implies r + s = -\dfrac43 \text{ and } rs = -4$

Then we find

$(r + s)^2 = r^2 + 2rs + s^2 \implies r^2 + s^2 = \left(-\dfrac43\right)^2 - 2(-4) = \boxed{\dfrac{88}9}$

8 0

2 years ago