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3 years ago

Please help. Thank you so much :)

Mathematics

2 answers:

Stolb23 [73]3 years ago

5 0

C. 6 pens for $6.42

Divide to find the number for one pen. then multiply

Brut [27]3 years ago

5 0

Divide 11.77 by 11 to get 1.07. Now multiply 6 time 1.07 to get 6.42. So letter C.

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A concrete pillar has the shape of a cylinder. It has a diameter of 8 meters and a height of 9 meters. If concrete costs $87 per

Komok [63]

Answer:

Cost, C = $28410.72

Step-by-step explanation:

We have, a concrete pillar has the shape of a cylinder.

Diameter of pillar is 8 m and ts height is 9 m

If concrete costs $87 per cubic meter, it is required to find the concrete cost for the pillar. For this lets find the area of cylindrical shape. So,

$A=2\pi rh+2\pi r^2\\\\A=2\times 3.14\times 4\times 9+2\times 3.14\times 4^2\\\\A=326.56\ m^2$

The cost of pillar at the rate of $87 per cubic meter will be :

$C=326.56\times 87\\\\C=\$28410.72$

8 0

3 years ago

At an end of the year sale, Gabriela bought more than 12 bottles of hand soaps and lotions. If x represents the number of hand s

nadya68 [22]

Answer:

the answer is b

Step-by-step explanation:

edge 2021

6 0

3 years ago

Read 2 more answers

6 children and 2 adults are going to the circus, children tickets are on sale, half the price of adult tickets totaling $54. How

inna [77]

Answer:

Price of 1 child ticket is $5.4

Price of 1 adult ticket is $10.8

Step-by-step explanation:

Given:-

6 children and 2 adults are going for circus.

Children ticket is half the price of adult ticket.

Total ticketing cost =$54

To find:-

Cost of 1 child ticket=?

Cost of 1 Adult ticket=?

Solution:-

Let price of 1 child ticket be x and price of 1 adult ticket be y,

therefore from the given data we get 2 equations,

$6x+2y=54$ -----------------------------------(1)

$x=\frac{1}{2} y$ --------------------------------(2)

Now, substituting the value of x from equation 2 in equation 1,

$6x+2y=54$

$6(\frac{1}{2} y)+2y=54$

$\frac{6}{2}y+2y=54$

$3y+2y=54$

$5y=54$

$\therefore y=\frac{54}{5}$

$\therefore y =10.8$ ------------------------(3)

Now, substituting the value of y from equation 3 in equation 2,

$x=\frac{1}{2} y$

$\therefore x=\frac{1}{2} \times 10.8$ ------------(from equation 3)

$\therefore x=\frac{10.8}{2}$

$\therefore x=5.4$ ----------------------(4)

As, x is price of 1 child ticket and y is price of 1 adult ticket,

Therefore price of 1 child ticket is $5.4 and price of 1 adult ticket is $10.8

7 0

3 years ago

Can you help me write this in standard form <br><img src="https://tex.z-dn.net/?f=y%20%3D%20%20%5Cfrac%7B3%7D%7B2%7D%20x%20-%20%

Karo-lina-s [1.5K]

I think it’s 15x-10y=2

3 0

3 years ago

The circumference of the circle is increasing at a rate of 0.5 meters per minute. What's the rate of change of the area of the c

morpeh [17]

Answer:

The rate of change of the area of the circle when the radius is 4 meters = 2 meters²/minute ⇒ answer 4

Step-by-step explanation:

* Lets revise the chain rule in the derivative

- If dy/da = m and dx/da = n, and you want to find dy/dx

∴ dy/dx = dy/da ÷ dx/da = m ÷ n = m/n

* In our problem we have

- The rate of increasing of the circumference dC/dt = 0.5 meters/minute

- We need the find the rate of change of the area of the circle

when the radius is 4 meters

- The common element between the circumference and the area

of the circle is the radius of the circle

* We must to find dC/dr and dA/dr and use the chain rule to

find dA/dr

- Find the rate of change of the radius dr/dt

∵ C = 2πr

- Find the derivative of C with respect to r

∴ dC/dr = 2π ⇒ (1)

∵ dC/dt = 0.5 meters/minute ⇒ (2)

- Divide (1) by (2) to get dr/dt by using chain rule

∵ dC/dt ÷ dC/dr = 0.5 ÷ 2π

∴ dC/dt × dr/dC = 0.5 × 1/2π ⇒ cancel dC together and change

0.5 to 1/2

∴ dr/dt = 1/2 × 1/2π = 1/4π ⇒ (3)

- Find the rate of change of the area dA/dt

∵ A = πr²

- Find the derivative of A with respect to r

∴ dA/dr = 2πr

∵ r = 4

∴ dA/dr = 2π(4) = 8π ⇒ (4)

- Multiply (4) by (3) to get dA/dt by using chain rule

∵ dA/dr × dr/dt = 8π × 1/4π ⇒ divide 8 by 4 and cancel π

∴ dA/dt = 2 meters²/minute

* The rate of change of the area of the circle when the radius is

4 meters = 2 meters²/minute

3 0

3 years ago