If 10 g of a radioactive substance are present initially and 4 yr later only 5.0 g​ remain, how much of the​ substance, to the nearest tenth of a​ gram, will be present after 9 ​yr?

[tex]0.3x = 2.1\\\\\implies 10\times 0.3x = 10 \times 2.1~~~~;[\text{Multiply both sides by 10}]\\\\\implies 3x = 21\\\\\implies x = \dfrac{21}3 = 7[/tex]

Answer:

x = 5

y = 4

Step-by-step explanation:

multiply the second equation by -1 and add the first equation to eliminate "x"

[tex]4x+6y=44\\-4x-2y=-28[/tex]
_____________

       [tex]4y=16[/tex]

[tex]y=16/4 =4[/tex]

Replace "y" in the first equation:

[tex]4x+6(4)=44[/tex]

[tex]4x+24=44[/tex]

[tex]4x=44-24[/tex]

[tex]x=20/4=5[/tex]

Hope this helps

Answer:

x = 5, y = 4.

Step-by-step explanation:

4x + 6y = 44        (A)

4x + 2y = 28        (B)

Subtract equations: (A) - (B).

0 + 4y = 16

y = 16/4

y = 4.

Now plug y = 4 into equation A:

4x + 6(4) = 44

4x = 44 - 24

4x = 20

x = 5.

Now check if these roots are correct by plugging them into equation B:

4x + 2y = 28

4(5) + 2(4) = 28   - check OK.

Answer:

60 feet?

Step-by-step explanation:

The area covered with grass, in square feeet, is the area of the shape of the yard.

The area of a yard can be calculated by determining the shape of the yard, and using the appropriate area formula of the shape to find the area of the yard.

Image of the yard is missing. However, assuming the yard is a rectangular shape with a dimension of 10 ft by 6 ft, therefore:

The square feet of grass Russell has = area of rectangle = (10)(6) = 60 ft²

In summary, the area covered with grass, in square feeet, is the area of the shape of the yard.

Learn more about area of yard on:

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Answer:

a) m problems, d days to complete.

m/d

b) m/15d

c)-if 15 was connected; 15d

if 15 WAS NOT connected, m problems

Answer:

f(0)=6

Step-by-step explanation:

It should be the third one because it is the only one that has the x-value in the parentheses and equals the y-value. (I think please someone back me up)

Answer: B

Step-by-step explanation:

Answer:

Below

Step-by-step explanation:

Diameter = 2r (r is radius) so the diameter is 40 inches

Circumference= 2pi r= 40pi or 125.663

Area= pi r^2= pi(20)^2= 400 pi pr 1256.637

Answer:

Diameter: 40 inches

Circumference: 40π, or ~125.66 inches

Area: 400π, or ~1256.64 inches

Step-by-step explanation:

Diameter is twice the radius, so 20×2 = 40 inches.

Circumference formula is C = 2πr, so plugging everything in, C = 2π×20,

and simplify, C = 40π, or C ≈ 125.66 inches.

Area formula is A = πr², so plugging everything in, A = π20², and then simplify, A = 40π, or A ≈ 1256.64 inches.

Answer:27

Step-by-step explanation:

Its pretty simple. Perimeter is the addition of all the sides. Add 4+9+8+6 to get 27.

Answer:

0.55

Step-by-step explanation:

In this question we need to find the Z score says that the area under the standard normal curve to the right is 0.29. So here in this question I have drawn here the normal distribution curve. So at this point we need to calculate the z value And with the probability of 29%. So to find the value of Z says that probability of zero great Small, that is equal to 0.29. So I can write this left hand side as one minus probability of less than small. It's called a 0.29 probability of zero, less than or equal to zero will do 0.29 one minus .29 which is equal to 0.71. So here we know the value of probability And we need to find the value of zero and there are various methods to calculate that one is the using the normal distribution tables and then there is the um MS Excel should. So from the table you can find the area closest to 0.71. So here the flow chart for finding me value. Using normal distribution table is given. So the first thing is from this table of the standard normal distribution, look at the probability value. So as you can see from this this is the snapshot of the table we need to find the probability value. So We have got the value of 0.71. So this is the nearest value to that you need to, next second is move left until the first column is reached. So move left until the first column is rich. This is the first column. Move upward until the top row is rich. Note that value. So here as you can see it is 0.5 and here it is 0.05. The intersection of the Roman columns gives the area of the two day loves. So which is 0.5 Plus 0.05 is equal to zero 55. This is the value of Z. Or as you can use the um xxl shoot to calculate the value of Z. Here, I have given the flow chart for that. Also you can use this to calculate the value of Z. So probability of mhm Less than or equal to 0.55 Is equal to 0.71. This is the answer. 0.55 is the answer for the solution.

Answer:

Step-by-step explanation:

The set of relationships can be formulated as three equations in three unknowns. These can be written as an augmented matrix and solved using a calculator.

Let x, y, z represent the numbers of compact, midsize, and luxury cars, respectively. Then the relations are ...

  x + y + z = 48 . . . . . . total number of cars purchased

  13x +25y +39z = 932 . . . . . total cost in thousands

  20x +27y +45z = 1265 . . . . daily rental revenue

The augmented matrix of coefficients looks like ...

  [tex]\left[\begin{array}{ccc|c}1&1&1&48\\13&25&39&932\\20&27&45&1265\end{array}\right][/tex]

And its solution is ...

  (x, y, z) = (25, 15, 8)

The agency should purchase 25 compacts, 15 midsize, and 8 luxury cars.

Using the permutation formula, it is found that there are 17,297,280 different signals consisting of 8 flags.

In this problem, the order in which the flags are visited is important, hence the permutation formula is used to solve this question.

The number of possible permutations of x elements from a set of n elements is given by:

[tex]P_{(n,x)} = \frac{n!}{(n-x)!}[/tex]

The first flag is blue, then the remaining 7 are taken from a set of 14, hence:

[tex]P_{(14,7)} = \frac{14!}{7!} = 17,297,280[/tex]

There are 17,297,280 different signals consisting of 8 flags.

More can be learned about the permutation formula at https://brainly.com/question/25925367

To find the slope ⇒ we must know the formula

   Formula = [tex]\frac{y2-y1}{x2-x1}[/tex]

Now let's solve and plug the known variables

     Slope = [tex]\frac{8-(-4)}{3-3} =\frac{12}{0}[/tex]

Nothing can be divided by zero

   ⇒ in this case, the slope is undefined

    *interesting fact: the line is vertical

Hope that helps!

Answer:

Step by step Solution :-

25X^2 + Y^2 = 25

A) Finding X value :-

1. Subtract Y^2 from both sides:

25X^2 = 25 - Y^2

2. Divide both sides by 25 :

( 25X^2 ) ÷ 25 = ( 25 - Y^2 ) ÷ 25

3. Dividing by 25 undo the multiplication by 25 :

X^2 = ( 25 - Y^2 ) ÷ 2

4. Divide ( 25 - Y^2 ) by 25 :

X^2 = ( - Y^2 ÷ 25 ) + 1

5. Take Square Root for both sides of equation ( before & after (=) ) :

X = √ ( 25 - Y^2 ) ÷ 5

X = - √ ( 25 - Y^2 ) ÷ 5

------------

Now that we knew what X value is, we'll figure out Y value too!

B) Finding Y value ( Finding Square Root ):-

Y^2 = 5√ ( 1 - X^2 )

1. Finding Square Root :

25X^2 + Y^2 = 25

2. Subtract 25X^2 value from both sides :

Y^2 = 25 - 25X^2

3. Take square root for both sides of equation :

Y = 5√ ( 1 - X^2 )

Y = - 5√ ( 1 - X^2 )

Answer:

Angle BFC is complimentary to AFB. Its measure is 12.

Step-by-step explanation:

Complementary angles add up to 90 degrees. When these two angles combine, it adds up to 90. 90-78 = 12. This angle's measure is 12.

Answer:

169 + 121 = 225

Step-by-step explanation:

It is not a right triangle
A squared + b square should equal c squared.
169 + 121 = 290

This is the  Answer :

true

Step-by-step explanation:

Let the amount of wheat is x and amount of corn is y.

The total amount of pasta is

Amount of protein in same pasta is

or

The graphical solution is attached

It is easy to solve the system by substitution

Then the value of y is

As we see x > y, so Leila is right

The above problem is solved using Multiple Representations.  Multiple representations are used to achieve a deeper comprehension of concepts related to the same operation.

We can arrive at whether the statement is true or false by solving for the value of Y using the graphical method. Where Y is the amount of wheat and X is the amount of corn.

Our function is given as follows:
X + Y= 57. ..........1

Recall that the total amount of pasta is 57 grams

Recall as well that the total amount of protein in the pasta is given as:

0.05x + 0.1y= 4grams.......2

By inputting equations 1 and 2 into the Desmos Graph, we have x to be equal to = 34, and y = 23. (please see the attached image).

Recall that Leila's assertion was that there is more corn in the Pasta. Since x is the amount of corn, then Leila's assertion is True that: x>y.

The algebraic solution is arrived at using substitution.

Rewriting equation (1), we have

y = 57 - x .......................(3)

Let us substitute y into equation (2) above. That gives us:

0.05x + 0.1(57 - x) = 4.........................(4)

Expanding the brackets, we obtain

0.05x + 5.7 - 0.1x = 4

Collecting like terms, we can rewrite the quation as:

0.1x - 0.05x = 5.7 - 4

0.05x = 1.7

Rewriting the equation such that it is subject to x, we have

x = 1.7/0.05

x = 34

If from the above, x = 34, inputting that into equation (3) above, we have

y = 57 - 34; Therefore,

y = 23

Learn more about Multiple Representation at:
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Answer:

-54/385

Step-by-step explanation:

Answer:

7

Step-by-step explanation:

We can setup this equation as x representing his number.  (x+13) * 3 = 9x -3.

Now, we just need to solve for x.  

3(x+13)=9x-3

x+13=3x-1

14=2x

x=7

Answer:

-46

Step-by-step explanation:

when a= 6 and ×=-5

-a + 8×= -6+8×-5

= -6+(-40)= -6-40= -46

Answer:

1/36

Step-by-step explanation:

The chance of you rolling a 5 is 1/6

While the chance of you rolling a 3 is a 1/6

If you want both a 5 then a 3 then you multiply the fractions

1/6 * 1/6 = 1/36

Answer:

Yes and yes

Step-by-step explanation:

Answer:

using of fractional exponents give us the value 6(x^2y^3)^1/2 or 6xy^3/2.

Answer:

b) 7.9968 × 1013 miles

Step-by-step explanation:

So one light-year equals 588 × 10^10

13.6 light-years equals 13.6 × 588 × 10^10 = 79968 × 10^9 = 7.9968 × 1013 miles

Using the normal distribution and the central limit theorem, it is found that the probability is of 0.1368 = 13.68%.

In a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

In this problem:

The mean and the standard error are given by:

[tex]\mu = p = 0.47[/tex]

[tex]s = \sqrt{\frac{p(1 - p)}{n}} = \sqrt{\frac{0.47(0.53)}{61}} = 0.0639[/tex]

The probability that less than 40% of the sample are looking to buy an SUV is the p-value of Z when X = 0.4, hence:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

By the Central Limit Theorem

[tex]Z = \frac{X - \mu}{s}[/tex]

[tex]Z = \frac{0.4 - 0.47}{0.0639}[/tex]

Z = -1.095

Z = -1.095 has a p-value of 0.1368.

0.1368 = 13.68% probability that less than 40% of the sample are looking to buy an SUV.

To learn more about the normal distribution and the central limit theorem, you can check https://brainly.com/question/24663213

Answer:

2923 is your p is equal to 2 and n