I need help with this question, I already know the answer but I need someone to explain step by step

Glenn needs 20 minutes to clean his room. If his little sister Veronika pulls things out while he is cleaning, it takes 60 minut

Bogdan [553]

Answer:

It takes 30 minutes

Step By Step:

The rate of Glenn in finishing a job would be equivalent to:

Rate (G) = 1

job / 20 minutes

While the rate of Veronika is:

Rate (V) = 1

job / x---> x is the unknown

Where 1 job for Glenn means completely cleaning his room while 1 job for Veronika means pulling out everything. Therefore the equation to use would be:

1 / 20 – 1 /

x = 1 / 60

The rate of

Veronika is subtracted from the rate of Glenn since Veronika is slowing Glenn

down. Solving for x:

Multiply both

sides by 60 x

(1 / 20 – 1 /

x = 1 / 60) * 60 x

3 x – 60 = x

2 x = 60

x = 30

Therefore it

takes 30 minutes for Veronika to pull everything out.

3 0

3 years ago

You read 9.75 pages in your science book and 24.5 pages of a play for English class. It takes you 1.2 minutes to read each page

Sladkaya [172]

9.75 * 1.2 = 11.7
24.5 * .8 = 19.6

11.7+19.6= 31.3 minutes

hope this helped :)

4 0

3 years ago

What is 6 times (12-4) in words?

Alika [10]

Six times twelve minus 4 equals forty-eight

3 0

3 years ago

Read 2 more answers

The diagram shows a regular octagon ABCDEFGH. Each side of the octagon has length 10cm. Find the area of the shaded region ACDEH

Zolol [24]

The area of the shaded region /ACDEH/ is 325.64cm²

Step 1 - Collect all the facts

First, let's examine all that we know.

We know that the octagon is regular which means all sides are equal.
since all sides are equal, then all sides are equal 10cm.
if all sides are equal then all angles within it are equal.
since the total angle in an octagon is 1080°, the sum of each angle within the octagon is 135°.

Please note that the shaded region comprises a rectangle /ADEH/ and a scalene triangle /ACD/.

So to get the area of the entire region, we have to solve for the area of the Scalene Triangle /ACD/ and add that to the area of the rectangle /ADEH/

Step 2 - Solving for /ACD/

The formula for the area of a Scalene Triangle is given as:

A = $\sqrt{S(S-a)(S-b)(S-c) square units}$

This formula assumes that we have all the sides. But we don't yet.

However, we know the side /CD/ is 10cm. Recall that side /CD/ is one of the sides of the octagon ABCDEFGH.

This is not enough. To get sides /AC/ and /AD/ of Δ ACD, we have to turn to another triangle - Triangle ABC. Fortunately, ΔABC is an Isosceles triangle.

Step 3 - Solving for side AC.

Since all the angles in the octagon are equal, ∠ABC = 135°.

Recall that the total angle in a triangle is 180°. Since Δ ABC is an Isosceles triangle, sides /AB/ and /BC/ are equal.

Recall that the Base angles of an isosceles triangle is always equal. That is ∠BCA and ∠BAC are equal. To get that we say:

180° - 135° = 45° [This is the sum total of ∠BCA and ∠BAC. Each angle therefore equals

45°/2 = 22.5°

Now that we know all the angles of Δ ABC and two sides /AB/ and /BC/, let's try to solve for /AC/ which is one of the sides of Δ ACD.

According to the Sine rule,

$\frac{Sin 135}{/AC/}$ = $\frac{Sin 22.5}{/AB/}$ = $\frac{Sin 22.5}{/BC/}$

Since we know side /BC/, let's go with the first two parts of the equation.

That gives us $\frac{0.7071}{/AC/} = \frac{0.3827}{10}$

Cross multiplying the above, we get

/AC/ = $\frac{7.0711}{0.3827}$

Side /AC/ = 18.48cm.

Returning to our Scalene Triangle, we now have /AC/ and /CD/.

To get /AD/ we can also use the Sine rule since we can now derive the angles in Δ ABC.

From the Octagon the total angle inside /HAB/ is 135°. We know that ∠HAB comprises ∠CAB which is 22.5°, ∠HAD which is 90°. Therefore, ∠DAC = 135° - (22.5+90)

∠DAC = 22.5°

Using the same deductive principle, we can obtain all the other angles within Δ ACD, with ∠CDA = 45° and ∠112.5°.

Now that we have two sides of ΔACD and all its angles, let's solve for side /AD/ using the Sine rule.

$\frac{Sin 112.5}{/AD/}$ = $\frac{Sin 45}{18.48}$

Cross multiplying we have:

/AD/ = $\frac{17.0733}{0.7071}$

Therefore, /AD/ = 24.15cm.

Step 4 - Solving for Area of ΔACD

Now that we have all the sides of ΔACD, let's solve for its area.

Recall that the area of a Scalene Triangle using Heron's formula is given as

A = $\sqrt{S(S-a)(S-b)(S-c) square units}$

Where S is the semi-perimeter given as

S= (/AC/ + /CD/ + /DA/)/2

We are using this formula because we don't have the height for ΔACD but we have all the sides.

Step 5 - Solving for Semi Perimeter

S = (18.48 + 10 + 24.15)/2

S = 26.32

Therefore, Area = $\sqrt{26.32(26.32-18.48)(26.32-10)(26.32-24.15)}$

A = $\sqrt{26.32 * 7.84*16.32 * 2.17)}$

A = $\sqrt{7,307.72}$ Square cm.

A of ΔACD = 85.49cm²

Recall that the shape consists of the rectangle /ADEH/.

The A of a rectangle is L x B

A of /ADEH/ = 240.15cm²

Step 6 - Solving for total Area of the shaded region of the Octagon

The total area of the Shaded region /ACDEH/, therefore, is 240.15 + 85.49

= 325.64cm²

See the link below for more about Octagons:
brainly.com/question/4515567

8 0

3 years ago

Which ordered pair is a solution to the equation?

Mama L [17]

Answer:

y=4/5x-3 - (-5, -7)

Step-by-step explanation:

So to solve this, lets just plug in each value for x, and see if the y value we get is equal to one of our answers.

So we have (-10, 5)

Well plug in -10 for 4/5x we get:

-40/5=-8

Next we take that value and solve:

y=-8-3

y=-11

The answer for this was 5, not -11.

Ill skip a few steps:

(10, -11):

Plug in 10 we get:

y=8-3 which is y=5. This is not right, for it needed to be -11.

Next we have (5, -1)

This gets us y=4-3 this is y=1 which is not -1. So thats not right.

Finally we have (-5, -7):

This gets us y=-4-3 this is y=-7. What was our y value? -7!

So the answer is (-5, -7)

I hope this helps! :)

6 0

3 years ago