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3 years ago

Will give brainliest

Mathematics

1 answer:

Reika [66]3 years ago

4 0

Answer:

30 hrs

Step-by-step explanation:

Downstream. In water, the direction along the stream is called downstream.

Upstream. In water, the direction against the stream is called upstream. Let the speed of a boat in still water be u km/hr and the speed of the stream be v km/hr, then. Speed downstream = (u + v) km/hr. Speed upstream = (u - v) km/hr

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The ratio of boys to girls in 8th grade at ESHS is 5:3. Calculate the number of boys if there are 210 girls. What is the total n

frosja888 [35]

Answer:

350

Step-by-step explanation:

If there are 210 girls, then the number of boys is (210÷3)x7=350.

5 0

3 years ago

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When y=7.5 x=2 what is the value of y when x is 2 1/4

swat32

<h2>Answer:</h2>

The value of y is 8.4375

<h2>Step-by-step explanation:</h2><h3>Known :</h3>

y = 7.5
x = 2

<h3>Asked :</h3>

The value of y when x is 2.25

<h3>Solution :</h3>

2/7.5 = 2.25/y

Do a cross multiplication,

2/7.5 = 2.25/y

=> 20/75 = 2.25/y

=> 75 . 2.25 = 20y

=> 168.75 = 20y

Reverse the equation,

168.75 = 20y

=> 20y = 168.75

Find the value of y,

20y = 168.75

=> y = 8.4375

<h3>Conclusion :</h3>

y = 8.4375

7 0

3 years ago

Hey. ill give brainliest to whoever answers this question, pls and thanks

lbvjy [14]

Answer:

whats the question

Step-by-step explanation:

3 0

3 years ago

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You have a wire that is 20 cm long. You wish to cut it into two pieces. One piece will be bent into the shape of a square. The o

Aleksandr [31]

Answer:

Therefore the circumference of the circle is $=\frac{20\pi}{4+\pi}$

Step-by-step explanation:

Let the side of the square be s

and the radius of the circle be r

The perimeter of the square is = 4s

The circumference of the circle is =2πr

Given that the length of the wire is 20 cm.

According to the problem,

4s + 2πr =20

⇒2s+πr =10

$\Rightarrow s=\frac{10-\pi r}{2}$

The area of the circle is = πr²

The area of the square is = s²

A represent the total area of the square and circle.

A=πr²+s²

Putting the value of s

$A=\pi r^2+ (\frac{10-\pi r}{2})^2$

$\Rightarrow A= \pi r^2+(\frac{10}{2})^2-2.\frac{10}{2}.\frac{\pi r}{2}+ (\frac{\pi r}{2})^2$

$\Rightarrow A=\pi r^2 +25-5 \pi r +\frac{\pi^2r^2}{4}$

$\Rightarrow A=\pi r^2\frac{4+\pi}{4} -5\pi r +25$

For maximum or minimum $\frac{dA}{dr}=0$

Differentiating with respect to r

$\frac{dA}{dr}= \frac{2\pi r(4+\pi)}{4} -5\pi$

Again differentiating with respect to r

$\frac{d^2A}{dr^2}=\frac{2\pi (4+\pi)}{4}$ > 0

For maximum or minimum

$\frac{dA}{dr}=0$

$\Rightarrow \frac{2\pi r(4+\pi)}{4} -5\pi=0$

$\Rightarrow r = \frac{10\pi }{\pi(4+\pi)}$

$\Rightarrow r=\frac{10}{4+\pi}$

$\frac{d^2A}{dr^2}|_{ r=\frac{10}{4+\pi}}=\frac{2\pi (4+\pi)}{4}>0$

Therefore at $r=\frac{10}{4+\pi}$ , A is minimum.

Therefore the circumference of the circle is

$=2 \pi \frac{10}{4+\pi}$

$=\frac{20\pi}{4+\pi}$

4 0

3 years ago

i need help asap!!The Pythagorean Theorem can be used on any triangle to determine the length of a missing side, given two of th

lbvjy [14]

Hi,

The answer is false.

Have a great day!

7 0

3 years ago

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