A certain radioactive isotope has a half-life of 50 years. A scientist determines that there are 200 grams of the radioactive material present today. How
Much of the isotope was present 200 years ago?

Answers

Answer 1

im guessing 800 50X4 = 200 and 200X4 = 800

i never learned this but i hope its correct.


Related Questions

ABCE is a parallelogram . determine the meaSure of

Answers

Answer:

D. 78°

Step-by-step explanation:

ABCD is a parallelogram.

Measures of the opposite angles of a parallelogram are equal.

Therefore,

[tex]3x = x + 52 \\ \\ 3x - x = 52 \\ \\ 2x = 52 \\ \\ x = \frac{52}{2} \\ \\ x = 26 \\ \\ m\angle B = (3x) \degree \\ \\ m\angle B = (3 \times 26) \degree \\ \\ m\angle B = 78\degree[/tex]

The proportions of blood types O, A, B, and AB in the general population of a particular country are known to be in the ratio 49:38:9:4, respectively. A research team, investigating a small isolated community in the country, obtained the following frequencies (i.e. observed number of cases) of blood type.
Blood type O A B AB
Frequency 87 59 20 4
Test the hypothesis that the proportions in this community do not differ significantly from those in the general population.

Answers

Answer:

The proportions differ significantly from those in the general population.

Step-by-step explanation:

We state our null and alternative hypotheses as

H0: p1= 49/100, p2= 38/100, p3= 9/100 and p4= 4/100 for a multinomial distribution involving four categories and n= 170

against

Ha: pi≠ pi0 for at least one value of i= 1,2,3,4

The significance level is set at ∝= 0.05

The test statistic under H0 is

χ² = ∑ (Oi- ei)²/ei

which has approximate chi square distribution with 3d.f  (n-1)

Computations: Under H0 the expected frequencies are

np10= Blood type O = 170 * 49/100= 83.3

np20 = Blood type A = 170 * 38/100= 64.6

np30 = Blood type B = 170 * 20/100= 11.76

np40 = Blood type AB = 170 * 4/100= 2.35

The value of χ² is computed as follows

Cell       Observed         Estimated        (Oi-ei)            (Oi-ei)²   (Oi-ei)²/ei

             Frequency      Frequency  

               Oi                    ei

1             87                        83.3               3.7               13.69        0.157

2            59                      64.6              -5.6                 31.36       0.531

3             20                     34                  -14                   196           9.8

4               4                      6.8                -2.8                  7.84         1.96      

∑             170                    188.7                                                  χ²= 12.43  

The critical region is χ²≥ χ²(0.05,3) = 7.82 for alpha = 0.05 and

χ²≥ χ²(0.01,3) = 11.34  for alpha = 0.01

As the calculated value lies in the critical region for both value of alpha we reject our null hypothesis and accept our alternate hypothesis. The proportions differ significantly from those in the general population.

what is equivalent to 6x-3y=12

Answers

Answer: x= 1/2y+2

Step-by-step explanation:

These points are linear. Find the slope.

Answers

Answer:

Slope = 3/2

Step-by-step explanation:

The slope of an equation is rise/run, or y/x.

Since the graph indicates that y rises by 3 and x rises by 2, the slope would be 3/2

Answer:

[tex]\frac{3}{2}[/tex]

Step-by-step explanation:

To find the slope of a line, you need to find the [tex]\frac{rise}{run}[/tex] between two points. I will be calculating the slope using the two points (2, 3) and (4, 6).

Slope = [tex]\frac{rise}{run}[/tex]

          = [tex]\frac{6-3}{4-2}[/tex]

          = [tex]\frac{3}{2}[/tex]

1 1/6 as an improper fraction

Answers

Answer:

The mixed number 1 1/6 converted into an improper fraction is 7/6.

Step-by-step explanation:

The improper fraction representation after converting of 1 1/6 is 7/6 where numerator is 7 and denominator is 6

To convert a mixed number to an improper fraction, we follow these steps:

Multiply the whole number by the denominator of the fraction.

In this case,  multiply 1 (the whole number) by 6 (the denominator), which gives  6.

Add the numerator to the result obtained in step 1.

The numerator in this case is 1. Adding 1 to 6 gives 7.

Place the result from step 2 as the numerator of the fraction, and keep the denominator the same.

The denominator remains 6.

Therefore, the improper fraction representation of 1 1/6 is 7/6.

Learn more about converting  fractions here:

https://brainly.com/question/15743041

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what does the dot (.) stand for in math

Answers

The dot stands for multiplication for example
4 •6 = 24 same as 4x6=24






If you’re talking about decimals

It is a point or dot we use to separate the whole number part from the fractional part of a decimal number. ... The decimal point separates the whole number from the fractional part. Example: In the number 257.16, the decimal point separates the whole number 257 from the fractional part 16, which is 16 hundredths.

Answer:

The dot is called a decimal. Its what separates the whole number and the fraction of the number.

Step-by-step explanation:

For example, 0.5 is saying half, or 50 out of 100.

Find the value of this expression if x = 5 and
y = 2.
xy^2/-3

Answers

Answer:

The value of this expression is:

[tex]\frac{xy^2}{-3}=-\frac{20}{3}[/tex]

Step-by-step explanation:

Given the expression

[tex]\frac{xy^2}{-3}[/tex]

Apply the fraction rule: a/-b = -a/b

[tex]\frac{xy^2}{-3}=-\frac{xy^2}{3}[/tex]

substituting x = 5, y = 2 in the expression

      [tex]=-\frac{\left(5\right)\left(2\right)^2}{3}[/tex]

       [tex]=-\frac{\left(5\right)\left(4\right)}{3}\:[/tex]

       [tex]=-\frac{20}{3}[/tex]

Therefore, the value of this expression is:

[tex]\frac{xy^2}{-3}=-\frac{20}{3}[/tex]

If t=2 what is the value of 13-2t

Answers

Answer:

9

Step-by-step explanation:

plug in t=2 into equation

so

13-2(2)

=13-4

=9

y=-x-4
4y - 2x = 8
Using the graphing method, which of the following choices is the solution of the system:
ОООО
(-6, -2).
(-4, 0)
Infinite solutions
No solution

Answers

Answer:

(-4 , 0)

Step-by-step explanation:

Graph attached

PICTURE BELOW....................

Answers

Answer: C

Step-by-step explanation: 45 divided by 18 is 2.5

Which of the following is an example of the distributive property?
1. 3(10 + 5) = 3(15)
2. 3(10 + 5) = (10 + 5)3
3. 3(10 + 5) = 30 + 15
4. 3(10 + 5) = 3(5 + 10)​

Answers

Answer:

3 - 30+15

Step-by-step explanation:

take the outside number and multiply it by each individual number in the parenthesis one at a time

a grandfather is nine times older than his granddaughter. in 8 years the grandfather will be five times older than his granddaughter how old is each of them now?

Answers

Answer:

Grandfather is 72 and granddaughter is 8

Step-by-step explanation:

f is grandfather and d is granddaughter.

f = 9d

f+8 = 5(d+8)

9d+8=5d+40

4d=32

d=8

f=9*8=72

Answer:

the grandpa is 72 the little girl is 8

Step-by-step explanation:

Please help!!!! I will mark brainliest!!

Answers

Answer:

1 4 6 8 Have a good night ✨ ☺

They are all exponential functions

I NEED HELP SOMEONE PLEASE HELP ME I NEED ANSWER BY TODAY SOMEONE PLEASE HELP

Answers

Answer:

D 100% d

Step-by-step explanation:

Suppose a normal distribution has a mean of 62 and a standard deviation of
4. What is the probability that a data value is between 57 and 65? Round your
answer to the nearest tenth of a percent.
A.66.8%
B.67.8%
C.69.8%
D.68.8%

Answers

Answer:

0.66772

Step-by-step explanation:

Given that :

Mean (m) = 62

Standard deviation (s) = 4

probability that a data value is between 57 and 65

P(57 < x < 65)

Using the relation :

(x - m) / s

P(x < 57) :

(57 - 62) / 4 = - 1.25

P(Z < - 1.25) = 0.10565 ( Z probability calculator)

P(x < 65) :

(65 - 62) / 4 = 0.75

P(Z < 0.75) = 0.77337 (Z probability calculator)

P(Z < 0.75) - P(Z < - 1.25)

0.77337 - 0.10565 = 0.66772

Answer:

66.8%

Step-by-step explanation:

Just took the test

Which of the following expressions shows the area, in square inches, of the circle?
(TT = 3.14)
O 3.3.14 - 22
O 3.14.32
03.14 22
03.14.3

Answers

Answer:

Step-by-step explanation:

the area of the circle A= 3.14*r^2

diameter is 6, radius is 6/2=3

it is choice 2

A=3.14*3^2

Find all missing angles

Answers

Answer:

m1=30

m2=41

m3=96

Step-by-step explanation:

m1=180-66-84

m2=180-96-43

m3=180-84

There are 13 apples in a basket. 5 of these apples are green. The rest of them are red.

What is the ratio of all apples in the basket to red apples?

What is the ratio of green apples to red apples?

Answers

Answer:

7:13

5:8

Step-by-step explanation:

Do 13 minus 5 and that is number of red apples. So the ratio is 8 to 13 total apples. So there are 5 green apples and 8 red apples so it’s going to be 5:8

Which statement best describes a unit rate?

1. John drove 350 miles in 5 hours

2. John drove 10 miles

3. John drove a car and a motorcycle

4. John drove 25 miles in 1 hour

Answers

Answer:

4. John drove 25 miles in 1 hour

Step-by-step explanation:

The unit rate is the number of something per unit. There should be a first number and the second number should always be 1.

The statement which best describes a unit rate is John drove 25 miles in 1 hour .

What is unit rate?

Unit rate can be defined as the ratio between two measurements with the second term as 1. It is considered to be different from a rate, in which a certain number of units of the first quantity is compared to one unit of the second quantity.

According to the question

Best describes a unit rate is that which have second term as 1 unit

So,

Only John drove 25 miles in 1 hour satisfy the condition ,

Hence, The statement which best describes a unit rate is John drove 25 miles in 1 hour .

To know more about unit rate here:

https://brainly.com/question/11258929

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Assume that T is a linear transformation. Find the standard matrix of T. T: R^3 right arrow R^2 , T(e 1) =(1,2), and T(e2 ) =( -4,6), and T(e 3 ) =(2, -6), where e 1, e2 , and e 3 are the columns of the 3 x 3 identity matrix. A= (Type an integer or decimal for each matrix element.)

Answers

Answer:

[tex]A = \left[\begin{array}{ccc}1&-4&2\\2&6&-6\end{array}\right][/tex]

Step-by-step explanation:

Given

[tex]T:R^3->R^2[/tex]

[tex]T(e_1) = (1,2)[/tex]

[tex]T(e_2) = (-4,6)[/tex]

[tex]T(e_3) = (2,-6)[/tex]

Required

Find the standard matrix

The standard matrix (A) is given by

[tex]Ax = T(x)[/tex]

Where

[tex]T(x) = [T(e_1)\ T(e_2)\ T(e_3)]\left[\begin{array}{c}x_1&x_2&x_3\\-&&x_n\end{array}\right][/tex]

[tex]Ax = T(x)[/tex] becomes

[tex]Ax = [T(e_1)\ T(e_2)\ T(e_3)]\left[\begin{array}{c}x_1&x_2&x_3\\-&&x_n\end{array}\right][/tex]

The x on both sides cancel out; and, we're left with:

[tex]A = [T(e_1)\ T(e_2)\ T(e_3)][/tex]

Recall that:

[tex]T(e_1) = (1,2)[/tex]

[tex]T(e_2) = (-4,6)[/tex]

[tex]T(e_3) = (2,-6)[/tex]

In matrix:

[tex](a,b)[/tex] is represented as: [tex]\left[\begin{array}{c}a\\b\end{array}\right][/tex]

So:

[tex]T(e_1) = (1,2) = \left[\begin{array}{c}1\\2\end{array}\right][/tex]

[tex]T(e_2) = (-4,6)=\left[\begin{array}{c}-4\\6\end{array}\right][/tex]

[tex]T(e_3) = (2,-6)=\left[\begin{array}{c}2\\-6\end{array}\right][/tex]

Substitute the above expressions in [tex]A = [T(e_1)\ T(e_2)\ T(e_3)][/tex]

[tex]A = \left[\begin{array}{ccc}1&-4&2\\2&6&-6\end{array}\right][/tex]

Hence, the standard of the matrix A is:

[tex]A = \left[\begin{array}{ccc}1&-4&2\\2&6&-6\end{array}\right][/tex]

what is 2 + 2= i need to know

Answers

4 :))))) hope this helps ya out
Explain:

Answer:

4 but what 1x1

Step-by-step explanation:

What do you think about this. Please I need help

Answers

Answer:

D

Step-by-step explanation:

Since its talking about INCREASING your numerators (The top of the fraction) would need to be adding up

equation 1: 5x + 3y=8
equation 2: 4x + 7y= 34

9x-10y=42 true

Answers

Answer:

true

Step-by-step explanation:

5x + 4x = 9x

3y + 7y = 10y

8 + 34 = 42

Answer:

False

Step-by-step explanation:

5x+3y=8

4x+7y=34

Then:

5x+4x+3y+7y=9x+10y

9x+10y=43 not 9x-10y

thx for helping me get smart and learing my math ava :D

Answers

Answer:

NICEE

Step-by-step explanation:

can someone check if I'm right?​

Answers

Answer:

your right!!!

Step-by-step explanation:

I think it’s correct

Line M contains points (4,3) and (1,2). Write a possible equation of line K that is
perpendicular to line M.

Answers

I believe the answer is y = -3x + 15
This is what I got from calculating it but I haven’t done this type of equation in a while

What is the volume of a cylinder, in cubic centimeters, with a height of 11 centimeters
and a base diameter of 6 centimeters? Round to the nearest tenths place

Answers

Answer: V = 311.0

Step-by-step explanation:

Formula: [tex]V = \pi r^2h[/tex]

[tex]V=\pi (3)^2 (11)[/tex]

[tex]V=99\pi[/tex]

V = 311.02

V = 311.0

ok so um yea plz help....and if you find them i will do 2 thingss............face reveil anddddddddd BRAINLEIST for you

Answers

Answer:

4

Step-by-step explanation:

all you have to do is divide 12 by 3

Answer:

4 if ur doing division or 3 over 12

                                       

Step-by-step explanation:

Here is a probability scale:
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

There are 3 white counters and 1 black counter in a bag.
I take one of the counters at random.
Put a cross on the probability scale to show the probability
that I have chosen the black counter.

Answers

Answer:

0.25

Step-by-step explanation:

3 white counters and 1 black counter,

3+1 = 4

the chances of you choosing the black counter is 1/4

1/4 can also be written as 0.25.

Answer:

The probability of choosing a black counter is 0.25.

Also the picture is attached for the mark on scale.

Step-by-step explanation:

Probability is the likeliness of occurrence of an event.

Given

There are three white and 1 black counter in the bag which means our sample space contains 3+1 = 4 elements

n(S) = 4

Let B be the event that the drawn out counter is black. As there is only one black counter

n(B) = 1

The probability of choosing a black counter is:

[tex]P(B) = \frac{n(B)}{n(S)}\\P(B) = \frac{1}{4} = 0.25[/tex]

Hence,

The probability of choosing a black counter is 0.25.

Also the picture is attached for the mark on scale.

what is the percent increase in 22 to 30

Answers

Answer:

36.37%

Step-by-step explanation:

30 - 22 = 8

100% * 8/22

800/22

36.37%

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