Mathematic 19 don’t understand

Answer: 1. 41.67years

2. £9.21

3. 7.75cm

Step-by-step explanation:

1. At a party, thirty people have an age of 30, forty have an age of 40 and fifty an age of fifty. What is their average age?

Total ages = (30 × 30) + (40 × 40) + (50 × 50) = 900 + 1600 + 2500 = 5000

Total number of people = 30 + 40 + 50 = 120

Average age = Total ages / Total number of people

= 5000/120

= 41.67 years

2. In a hardware shop, there are 30 spanners costing £6, 55 hacksaws costings £9 and 10 soldering irons costings £20. What is the average cost per item?

Total cost of items = (30 × £6) + (55 × £9) + (10 × £20) = £180 + £495 + £200 = £875

Total number of items = 30 + 55 + 10 = 95

Average cost per item = £875/95 = £9.21

3. Using this frequency table, find the average height of a turnip.

Height (to nearest cm)

6cm 7cm 8cm 9cm 10cm

Frequency: 3 8 12 4 1

Total height = (3 × 6cm) + (8 × 7cm) + (12 × 8cm) + (4 × 9cm) + (1 × 10cm) = 18cm + 57cm + 96cm + 36cm + 10cm = 217cm

Total number of turnips = 3 + 8 + 12 + 4 + 1 = 28

Average height = 217cm/28 = 7.75cm

Answer:

a²-7ab+7b²-2

Step-by-step explanation:

3a²-5ab+7b²+3 - ( 2a²+2ab+5 ) = 3a²-5ab+7b²+3 - 2a²-2ab-5 = a²-7ab+7b²-2

Answer:

Y =1.2X +-1.6

Step-by-step explanation:

x1 y1  x2 y2

3 2  -2 -4

(Y2-Y1) (-4)-(2)=   -6  ΔY -6

(X2-X1) (-2)-(3)=    -5  ΔX -5

slope= 1  1/5    

B= -1  3/5    

Y =1.2X +-1.6    

There are two triangles here: ABC and ADF. These triangles are similar, and thus proportional. So, we can set up a proportion between the left side of each triangle and the base of each triangle.

AB / AD = BC / DE

4 / (4 + BD) = 5 / 9

---AD is made up of AB and DB. We know AB, but not BD, so we need to find its value to find the length of AD.

5(4 + BD) = 9 x 4

20 + 5BD = 36

5BD = 16

BD = 3.2

AD = AB + BD

AD = 4 + 3.2

AD = 7.2

Hope this helps!

Answer:

...=

Step-by-step explanation:

First step to these problems will be to move the -11 to the side with the 107_

That will give us 35x=107_ +11.

Next, we know 35=5 times 7, and be now can say that 107_+11 will be a multipe of 5 and 7 at the same time. If it's a multiple of 5, then it has to end in a five or zero, so the blank can be four or nine. If it has to be a multiple of seven, too, than the only 1070 because that is divisible by 7, whereas 1075 is not.

I hoped you liked this answer. If you have any more questions, you can always ask me!

It should be noted that in the equation 35x - 11 = 107, x will be 3.371.

To solve the equation 35x - 11 = 107, we can follow these steps:

Add 11 to both sides of the equation to isolate the term with the variable:

35x - 11 + 11 = 107 + 11

This simplifies to:

35x = 118

Divide both sides of the equation by 35 to solve for x:

(35x) / 35 = 118 / 35

This simplifies to:

x = 118 / 35

The result, in decimal form, is approximately:

x ≈ 3.37

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Answer:23

Step-by-step explanation:

Answer:

x=5

Step-by-step explanation:

(5x+2)/3 = 9

Multiply each side by 3

(5x+2)/3 *3 = 9*3

5x+2 = 27

Subtract 2 from each side

5x+2-2 = 27-2

5x = 25

Divide by 5

5x/5 = 25/5

x =

Answer:

828

Step-by-step explanation:

Multiple the side length by the dilation

36 x 23 = 828

[ (10)(x^3)(y^2) / (5)(x^-3)(y^4) ]^-3

[ (2)(x^3)(y^2) / (x^-3)(y^4) ]^-3

[ (2)(x^6)(y^2) / (y^4) }^-3

[ (2)(x^6)(y^-2) ]^-3

(2^-3)(x^-18)(y^6)

---Not simplified (contains negative exponents)

(1/8)(x^-18)(y^6)

---Fully simplified

(y^6) / (8)(x^18)

Hope this helps!

Answer: Approximately 17.69

Step-by-step explanation:

The formula needed to find the third side of this equation is the Pythagorean theorem. Which is as follows:

[tex]a^2+b^2=c^2\\c=\sqrt{a^2+b^2}[/tex]

The difference between the two is that the first one after you do [tex]a^2+b^2[/tex] you still need to square root the answer you get to get the third side, aka. the hypotenuse. If you do the second method, you get the answer after you do the calculation which is a lot easier.

Below are the calculations needed to be made in both ways:

[tex]12^2+13^2=313\\\sqrt{313}= 17.69[/tex]   17.69 was rounded to the hundredths place.

[tex]\sqrt{12^2+13^2}=17.69[/tex]   once again this answer was rounded to the hundredths place.

[tex]a^2+b^2[/tex] are respectively for the sides of the triangles.

[tex]c^2[/tex] is respectively for the hypothenuse, which is the longest side, and across from the right angle (located by a box).

Answer:

5 or 17.69

Step-by-step explanation:

1st case senario:

c^2=a^2+b^2

c^2=12^2+13^2

c^2=144+169

c^2=313

c^2=[tex]\sqrt{313}[/tex]

c=17.69

2nd case senario:

144+b^2=169

b^2=169-144

b^2=25

b^2=[tex]\sqrt{25}[/tex]

b+5

Answer:

there may be mistake in the question

Step-by-step explanation:

chắc là nó như này à :>♡♡♡

Answer:

C.The value of a motorcycle decrease by 12% each year

D.Every year, the number of online subscribers to a service is 4 times what it was the previous year

Step-by-step explanation:

A function is said to be exponential if it changes (increases or decreases) by a fixed percentage or proportion over a certain period of time.

From the options given, only options C and D is defined as changing based on a certain percentage. And option D cgbages by a clfixed proportion from the initial value.

The option that represents the exponential function are situation C) and D) and this can be determined by making the mathematical expression of each situation.

Try to make a mathematical expression of the situation given below in order to check which option shows an exponential function.

A) According to the given data, in the first row there are 6 cans, in the second row there are 12 cans, in the third row there are 18 cans, and so on. Now, let 'a' be the total number of rows then, the mathematical expression of this situation is given by:

= 6a

This situation is not representing the exponential function.

B) According to the given data, in the first month there are 20 patients, in the second month there are 40 patients, and so on. Let the total number of months be 'b' then the mathematical expression is given by:

= 20b

This situation is not representing the exponential function.

C) According to the given data, in the first year the value of the motorcycle decrease 12%, in the second month the value decreased by 24% of the initial value, and so on. So, the price of motorcycle decreases exponentially. Therefore, this option is correct.

D) According to the given data, every year, the number of online subscribers to service is 4 times what it was the previous year. The mathematical expression of this situation is:

= [tex]4^x[/tex]

where 'x' is the number of years. Therefore, this option is correct.

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Answer:

5 km would be the answer

Step-by-step explanation:

For 45-45-90 triangles, the values are x, x, for the less long sides, then for the hypotenuse it's x sqrt2, because that is the rule for 45-45-90 triangles. So since in this problem, the value for the hypotenuse is 5sqrt2 km, the c value would be 5 km. Hope this helps!

Answer:

um ok the laiyflylfug;ou;

Step-by-step explanation:

Answer:the answer is 9

Step-by-step explanation:

Answer:

4x^2 +9x/4 -7

Step-by-step explanation:

f(x) =x/4 - 3

g(x) = 4x^2 + 2x - 4

(f +g)(x) = x/4 - 3  +  4x^2 + 2x - 4

             = 4x^2 + 8x/4+x/4 -7

             = 4x^2 +9x/4 -7

Answer:

See below.

Step-by-step explanation:

Part A:

triangle QPR and triangle PSR are similar

Part B:

Triangle QPR is a right triangle with right angle QPR.

Triangle SPR is a right triangle with right angle PSR.

Angle QPR of triangle QPR corresponds to and is congruent to angle PSR of triangle PSR.

Angle R of triangle QSR corresponds to and is congruent to angle R of triangle PSR.

The similar triangles by AA Similarity are

triangle QPR and triangle PSR

Part C:

QR/PR = PR/SR

16/PR = PR/4

PR² = 16 * 4

PR² = 64

PR = 8

Answer:

0.85y

Step-by-step explanation:

Cost of the wrist watch = $y

Present percentage = 100%

Percentage Loss = 15%

Selling price = (Present percentage - Percentage Loss) * Cost of the wrist watch

= (100% - 15%) * y

= 85% * y

= 85/100 * y

= 0.85 * y

= 0.85y

Selling price = 0.85y

Answer:

and practice problems to learn how to find and evaluate composite functions. ... If f(x)=(1/x) and (f/g)(x)=((x+4)/(x^2+2x)), what is the function g?

Answer:

Let the number be x

Given that

⇒(x+

3

2

)×2=

3

16

⇒x+

3

2

=

3

8

⇒x=

3

8

−

3

2

⇒x=

3

6

⇒x=2

Thus the number is 2

Answer:

According to me,

y = 3x ^ 2 + 6x- 12  

(a=3; b=6; c= -12)

• Ta có Δ=b^2 -4ac

             = 6^2 -4*3*( -12)

             =180

• X= (-b+√Δ)/2a

              ≈ 3.2

• X= (-b-√Δ)/2a

 ≈ -3.2

Khi đó: y= 948/25

       Và: y= -12/25

Vậy : A(3.2: 948/25)

       B(-3.2; -12/25)

Step-by-step explanat bion :

Los tres cantos volverán a coincidir en 154 minutos.

Dado que en una granja hay un gallo, un canario y un azulejo, suponiendo que el gallo canta cada 7 minutos, que el canario lo hace cada 14 minutos y el azulejo, cada 22 minutos, si en este momento cantaran al mismo tiempo las tres aves, para determinar en cuántos minutos volverán a  coincidir los tres cantos se debe realizar el siguiente cálculo:

Debe obtenerse el múltiplo común menor entre 7, 14 y 22. Dado que todo múltiplo de 14 será también múltiplo de 7 (pues 14 no es otra cosa que dos veces 7), debe obtenerse el múltiplo común menor entre 14 y 22. Entonces, debe descomponerse ambos números en factores primos:

Posteriormente, deben multiplicarse los factores no comunes por el factor común, es decir, 7 x 11 x 2, cuyo resultado es igual a 154. Así, los tres cantos volverán a coincidir en 154 minutos.

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Answer:

-0.6

Step-by-step explanation:

Answer:

⅗ as a decimal is -0.6

Answer:

27 games

Step-by-step explanation:

The probability of them winning is 3 out of 5 games.

First, multiply 45 by [tex]\frac{3}{5}[/tex]

[tex]\frac{45}{1} *\frac{3}{5}[/tex]

[tex]\frac{135}{5}[/tex]

27 games.

You could also just multiply 45 by 3 then divide by 5. Mostly the same thing

I hope this helps!

Answer:

8

Step-by-step explanation:

Make a ratio

2:9 = 11

In total there will be 11 cups of solution.

2:9 = 11

?:36 = ?

Divide

36 / 9 = 4

Now that you have found the scale factor, multiply

2 × 4 = 8

So, you will need 8 cups of shampoo concentrate.

Answer:

24°c

Step-by-step explanation:

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Answer:

2.75, or 2 3/4

Step-by-step explanation:

Cross multiply first to get:

4y = 11

Divide by 4 on both sides

y = 2.75

Now, simplify to a mixed number or keep it as a decimal to get 2.75, or 2 3/4.

Hope this helps!

If there is something wrong, just let me know.

Answer:

2.75

Step-by-step explanation:

1/y = 4/11 cross multiply the expressions

4y = 11 divide both sides by 4

y = 2.75

Answer:

graph b is your answer

Step-by-step explanation:

I hope this help and have a great day

Answer:

The answer is B.

Step-by-step explanation: