At a particular school, all students participate in at least one out of three activities: debate, music, and community service. 3 students do all three activities, 21 students do two or more activities, half of all students participate in music, and the ratio of participants in debate, music, and community service, respectively, is $5:4:3$. What is the total number of students at the school

Answer:

Amy has 12 5¢ coins

Step-by-step explanation:

Let x represent 20¢ coins and y represent 5¢ coins.

Amy has four more 20¢ coins than 5¢ coins. Hence:

[tex]x=y+4[/tex]

And the total value of all her coins is $3.80. Thus:

[tex]0.2x+0.05y=3.8[/tex]

This yields a system of equations:

[tex]\displaystyle \begin{cases} x=y+4 \\ 0.2x+0.05y=3.8\end{cases}[/tex]

We can solve by substitution. Substitute the first equation into the first:

[tex]\displaystyle 0.2(y+4)+0.05y=3.8[/tex]

Distribute:

[tex]\displaystyle 0.2y+0.8+0.05y=3.8[/tex]

Combine like terms:

[tex]\displaystyle 0.25y = 3[/tex]

And divide both sides by 0.25. Hence:

[tex]y=12[/tex]

Thus, Amy has 12 5¢ coins.

Using the first equation:

[tex]x=y+4[/tex]

Substitute:

[tex]x=(12)+4=16[/tex]

Thus, Amy has 16 20¢ coins.

In conclusion, Amy has 12 5¢ coins and 16 20¢ coins.

Given:

Volume of a sphere is [tex]\dfrac{28}{3}[/tex] times the surface area.

To find:

The surface area and the volume of the sphere.

Solution:

Volume of a sphere:

[tex]V=\dfrac{4}{3}\pi r^3[/tex]              ...(i)

Surface area of a sphere:

[tex]A=4\pi r^2[/tex]                      ...(ii)

Where, r is the radius of the sphere.

Volume of a sphere is [tex]\dfrac{28}{3}[/tex] times the surface area.

[tex]V=\dfrac{28}{3}\times A[/tex]

[tex]\dfrac{4}{3}\pi r^3=\dfrac{28}{3}\times 4\pi r^2[/tex]

Multiply both sides by 3.

[tex]4\pi r^3=112\pi r^2[/tex]

[tex]\dfrac{\pi r^3}{\pi r^2}=\dfrac{112}{4}[/tex]

[tex]r=28[/tex]

Using (i), the volume of the sphere is:

[tex]V=\dfrac{4}{3}\times \dfrac{22}{7}\times (28)^3[/tex]

[tex]V\approx 91989[/tex]

Using (ii), the surface area of the sphere is:

[tex]A=4\times \dfrac{22}{7}\times (28)^2[/tex]

[tex]A=9856[/tex]

Therefore, the surface area of the sphere is 9856 sq. units and the volume of the sphere is 91989 cubic units.

Answer:

C. b2 – 4ac = 4

Step-by-step explanation:

Answer:

The graph is possible for  

Step-by-step explanation:

we know that

The discriminant of a quadratic equation of the form

is equal to

If D=0 the quadratic equation has only one real solution

If D>0 the quadratic equation has two real solutions

If D<0 the quadratic equation has no real solution (complex solutions)

In this problem , looking at the graph, the quadratic equation has two real solutions (the solutions are the x-intercepts)

so

therefore

The graph is possible for

...............................................................................................................................................

Answer:

b^2 – 4ac = 4

...............................................................................................................................................

Answer:

1)9-7+x

2+x

2)8-2x+5x

8+3x

3)-x+3x-9

2x-9

4)4x-4x-6

-6

you have to group the like terms

I hope this helps and sorry if they are wrong

Answer:

Step-by-step explanation:

757 minutes = 12 hours 37 minutes

Answer:

32 ounces

Step-by-step explanation:

Step-by-step explanation:

1600-1472=128

128/1600×100

Answer:

look below bestie

Step-by-step explanation:

ok so i dont know most of it (sryy) but the area of the entire pizza is 535.84in², the radius of the pizza is about 13.05 and yea. thats all i got

Answer:

9. Hypotenuse = √(19.1²+11.3²) = √492.5 = 22.2 m²

10. Area = (34×40)/2 + (17²×π/2)

= 680 + 453.96

= 1133.96 cm²

Answered by GAUTHMATH

Answer:

You will need to order 3.75 cubic yards of topsoil.

Step-by-step explanation:

Since you want to put a 3 inch thick layer of topsoil for a new 15 ft by 26 ft garden, and the dirt store sells by the cubic yards, to determine how many cubic yards will you need to order given that the store only sells in increments of 1/4 cubic yards, the following calculation should be performed:

3 inches = 0.25 feet

15 x 26 = 390 x 0.25 = 97.5

1 cubic yard = 27 cubic feet

97.5 cubic feet = 3.61 cubic yards

3.75 = 1/4 x 15

Therefore, you will need to order 3.75 cubic yards of topsoil.

1.

C. 5x + 4 - 2x is an algebraic expression

Answer:

34

Step-by-step explanation:

x² = 30² + 16²

(pythagoras theorem)

x = Square root 30² + 16²

x = 34

Answer:

yes please, ask the question

You want to pull out the square roots of each term since they are both perfect squares.

Factor using the difference of squares formula: a2-b2=(a+b)(a-b)

This formula allows the middle term to cancel out.

=x2 - 49

=(x + 7)(x - 7)

ANSWER: (x + 7)(x - 7)

Hope this helps! :)

Answer:

£510

Step-by-step explanation:

5% of 3400 is 170. SInce she gets that much money every year, after 3 years she'll have 3*170 = £510.

Answer: Simple Interest = PRT

P= 3400

R = 5% = 5/100

T = 3

=> 3400 × 5/100 × 3 = 510

=》3400 + 510 = 3910

Step-by-step explanation:

Answer:

Step-by-step explanation:

let the  numbers be x and y.

x+y=16

x-y=6

add

2x=22

x=22/2=11

11+x=16

x=16-11=5

product xy=11×5=55

Complete question is;

In the triangles attached , DF is congruent to MN,DG is congruent to MP, angle D is congruent to angle P. Can you prove that triangle DFG is congruent to MNP.

Answer:

Proved below

Step-by-step explanation:

From the attached triangles, we can see that;

∠D corresponds to ∠M

∠F corresponds to ∠N

∠G corresponds to ∠P

But we are told that ∠D is congruent to ∠P. Thus, since we have 2 other congruent sides in the triangles, we can conclude that Side-Angle-Side Postulate (SAS) congruency theorem that triangle DFG is congruent to MNP.

Answer:

x2 + xy2 + y 4=（x+y^2)^2-xy^2

Step-by-step explanation:

Answer:

irrational

Step-by-step explanation:

Answer:

? ≈ 65°

Step-by-step explanation:

Using the cosine ratio in the right triangle

cos? = [tex]\frac{adjacent}{hypotenuse}[/tex] = [tex]\frac{8}{19}[/tex] , then

? = [tex]cos^{-1}[/tex] ([tex]\frac{8}{19}[/tex] ) ≈ 65° ( to the nearest degree )

does it give the answer choice or is it a blank space?

Answer:

B is correct_

Answer:

10*(5) - 2*(2)^3

= 50 - 2*8

= 50 - 16

=34

Answer:

Step-by-step explanation:

với x=5 và y=2

phương trinh trở th a

10*  5 - 2 * 2^ 3

=50 -  2*8

=50 - 16

=34

Answer:

60

Step-by-step explanation:

Multiply length times width times height

Answer:

C or 104

Step-by-step explanation:

I assume this is surface area, and I don't know what kinda sadist person would make everyone learn in "Total Area," but it is what it is.

So, to find total area, we need to literally multiply every different number with the other.

(You should not do it the way I did, as I did it in the easiest and simpliest way to understand possible.)

Actually, you get the length, width, and height of a figure and do what is below pretty much.

You multiply the length by the width, the length by the height, and the width by the height (doesn't have to be in this order, this is just to make it easy to remember which ones you did.)

We multiply the

5 * 6

5 * 2

and then the

6 * 2

This accounts for every possible case, as multiplying 2 * 5 gives the same thing as the second expression anyways.

So we then solve these three expressions.

5 * 6 = 30

5 * 2 = 10

and then the

6 * 2 = 12

And we add them to get

30 + 10 + 12

= 52.

Then we multiply by 2, because there are two cases of each face of the shape.

You need to remember that there is 3 other faces on the shape you are looking at, it's just that the shape/figure is facing you in a way that you can't see them.

After multiplying by 2, we get

52 * 2

= 104, which is C.

TAKE A SCREENSHOT NOT A PICTURE AS WE DON'T NEED TO SEE SOME 420P MONITOR FROM 1987 THAT SHOWS EVERY PIXEL PLEASE AND THANK YOU :D

Answer:

380

Step-by-step explanation:

This is a bit nasty. It depends on how you read the 20 miles more and what you do with it. The best and most careful way to do it is do it a long way setting up the two equations carefully.

Second day

Let the time travelled = t

Let the speed travelled = 60 mph

d2 = 60*t

First Day

40*(t + 2) = d1

but d1 = d2 + 20 because he travelled 20 miles further on d1

40 * (t + 2) = d2 + 20

d2 however = 60*t

40*(t+2 ) = 60*t + 20          Remove the brackets

40t + 80 = 60t + 20           Subtract 20 from both sides

40t + 60 = 60t                   Subtract 40t from both sides

60 = 20*t                           Divide by 20

t = 60/20

t = 3 hours.

Day 2 = 60 + t = 180

Day 1 = 40*5  = 200

Total distance = 380

Where did that 20 miles go? It was just an observation about the difference in distance travelled between the 2 days.

The total distance the driver traveled in the two days is 260 miles

From the question, on the first day, the driver was going as a speed of 40 mph.

Let s be speed

∴ [tex]s_{1}= 40mph[/tex]

On the second day, he increased the speed to 60 mph

∴ [tex]s_{2}= 60mph[/tex]

From the statement- If he drove 2 more hours on the first day

Let time be t

Then

[tex]t_{1}= t_{2} + 2[/tex] hrs

and traveled 20 more miles

Let d be distance  

Then,

[tex]d_{1}= d_{2} + 20[/tex] miles

From the formula

Distance = Speed × Time

Then,

[tex]d = s \times t[/tex]

∴ [tex]d_{1} = s_{1} \times t_{1}[/tex]

From above,

[tex]d_{1}= d_{2}+20[/tex] miles

[tex]s_{1}= 40mph[/tex]

[tex]t_{1}= t_{2} + 2[/tex] hrs

Putting these into

[tex]d_{1} = s_{1} \times t_{1}[/tex]

[tex]d_{2} + 20 = 40\times (t_{2}+2)[/tex] ...... (1)

But,

[tex]Time = \frac{Distance}{Speed}[/tex]

∴ [tex]t_{2}= \frac{d_{2} }{s_{2} }[/tex]

From above, [tex]s_{2}= 60mph[/tex]

∴ [tex]t_{2}= \frac{d_{2} }{60}[/tex]

Put this into equation (1)

[tex]d_{2} + 20 = 40\times (t_{2}+2)[/tex]

[tex]d_{2} + 20 = 40\times (\frac{d_{2}}{60} +2)[/tex]

[tex]d_{2} + 20 = \frac{2}{3}d_{2} +80\\d_{2} = \frac{2}{3}d_{2} +80-20\\d_{2} = \frac{2}{3}d_{2} +60[/tex]

Multiply through by 3

[tex]3\times d_{2} = 3\times \frac{2}{3}d_{2} +3 \times 60\\3d_{2} = 2d_{2} + 120\\3d_{2} -2d_{2} = 120[/tex]

∴ [tex]d_{2} = 120[/tex] miles

∴The distance traveled on the second day is 120 miles

For the distance traveled on the first day,

Substitute [tex]d_{2}[/tex] into the equation

[tex]d_{1}= d_{2}+20[/tex] miles

∴ [tex]d_{1}= 120+20[/tex]

[tex]d_{1}= 140[/tex] miles

∴ The distance traveled on the first day is 140 miles

The total distance traveled in the two days = [tex]d_{1} + d_{2}[/tex]

The total distance traveled in the two days = 120 miles + 140 miles

The total distance traveled in the two days = 260 miles

Hence, the total distance the driver traveled in the two days is 260 miles

Learn more here: https://brainly.com/question/23531710

Answer: 380.1

Step-by-step explanation:

The area of a circle is pi*r^2. So 11 times 11 is 121. Then multiply by pi. When multiplies by pi you get 380.132711084. rounded to the nearest tenth is 380.1.

Answer:

10.5 %

Step-by-step explanation:

Here .

let the Cost Price be 'x'

the..

by the question..

the marked price was fixed to make 30% profit

then..

the marked price will be

x+ 30% of x

= x + 30/100 × x

=x+ 0.3x

=1.3x

soo .. the marked price is 1.3x

now.. after allowing 15% discount..

the selling price will be

1.3x - 15% of 1.3x

= 1.3x - 0.195x

= 1.105x

thank you...

plzz mark me brainliest now

now..

profit made = 1.105x-x

= 0.105x

soo .

in percentage..

profit percent = profit/cp × 100%

= 0.105x/x × 100%

= 10.5 %

Answer:

An isometry preserves all the following except orientation .

Answer:

Infenitely many solutions

Answer:

Pressure is 80,000 pascals.

Step-by-step explanation:

Area:

[tex] = { \bf{ 30 \times {10}^{ - 4} \: {m}^{2} }}[/tex]

Pressure:

[tex]{ \bf{pressure = \frac{force}{area} }} \\ \\ { \tt{ = \frac{240}{30 \times {10}^{ - 4} } }} \\ = { \tt{80000 \: pascals}}[/tex]