Element X is a radioactive isotope such that every 24 years, its mass decreases by
half. Given that the initial mass of a sample of Element X is 70 grams, how long
would it be until the mass of the sample reached 61 grams, to the nearest tenth of a
year?

Answers

Answer 1

Answer:

Step-by-step explanation:

We get to use the simple version of the half life equation:

[tex]N=N_0(\frac{1}{2})^{\frac{t}{H}[/tex] where N is the amount of radioactive element left after a specific number of years,

N0 is the initial amount of the element,

t is the number of years (our unknown), and

H is the Half life of the element. For us,

N is 61

N0 is 70,

t is unknown,

H is 24 years. Filling in:

[tex]61=70(.5)^{\frac{t}{24}[/tex]. We begin by dividing both sides by 70 to get:

[tex].8714285=(.5)^{\frac{t}{24}[/tex] and then take the natural log of both sides:

[tex]ln(.8714285=ln(.5)^{\frac{t}{24}[/tex] which allows us to bring down the exponent to the front on the right side:

[tex]ln(.8714285)=\frac{t}{24}ln(.5)[/tex]. We divide both sides by ln(.5) to get:

[tex].1985457976=\frac{t}{24}[/tex] and then multiply both sides by 24 to get:

t = 4.8 years


Related Questions

How many different squads of 5 players can be picked from 10 basketball players? ​

Answers

Answer:

2 squads of five can be picked from 10 basketball players

Step-by-step explanation:

To solve this problem you have to divide 10 ÷ 2 which equals to 5.

What’s the answer and How do you do these

Answers

it’s 45 degrees; since the line is intersecting 2 parallel lines, the angles are the same. similarly, the angle to the right of “angle 2” would be 135 degrees

The accompanying table shows the value of a car over time that was purchased for 14100 dollars, where x is years and y is the value of the car in dollars. Write an exponential regression equation for this set of data, rounding all coefficients to the nearest thousandth. Using this equation, determine the value of the car, to the nearest cent, after 15 years.

Answers

Answer:

equation: 14506.226(0.870)^x

answer: 1796.15

Step-by-step explanation:

Plugging in the tables into your calcuator

a= 14506.226

b= .870

y=ab^x

y= 14506.226(0.870)^x

= 1796.15

The equation of the exponential regression is [tex]\rm y = 14100 \ e^{-0.087x}[/tex]. And the value of a car after 15 years is $ 3,823.53.

What is an exponent?

Exponential notation is the form of mathematical shorthand which allows us to write complicated expressions more succinctly. An exponent is a number or letter is called the base. It indicates that the base is to raise to a certain power. X is the base and n is the power.

The accompanying table shows the value of a car over time that was purchased for 14100 dollars, where x is years and y is the value of the car in dollars.

The exponential regression equation will be given as

[tex]\rm y = A_o e^{kx}[/tex]

Where A₀ is the coefficient of exponential regression and k is the constant.

For x = 0, the value of y will be $ 14100. Then we have

[tex]\rm 14100= A_o e^{k*0}\\\\ A_o \ \ \ \ = 14100[/tex]

Then the equation will be

[tex]\rm y = 14100 \ e^{kx}[/tex]

For x = 1, the value of y will be $12,929. Then we have

[tex]\rm 12929= 14100 e^{k*1}\\\\ e^k \ \ \ \ = 0.91695[/tex]

Taking ln both sides, then we have

[tex]\begin{aligned} \rm ln\ e^k &= ln \ 0.91695\\\\\rm k*ln \ e &= -0.087\\\\\rm k &= -0.087 \end{aligned}[/tex]

Then the equation will be

[tex]\rm y = 14100 \ e^{-0.087x}[/tex]

Then after 15, the value of a car will be

[tex]\rm y = 14100 \ e^{-0.087*15}\\\\\rm y = 14100 * 0.2712\\\\\rm y = 3823.53[/tex]

More about the exponent link is given below.

https://brainly.com/question/5497425

Evaluate the following expression. 45%[6x(17-9)-30]

Answers

Answer:

tdxutdxfhdxfhx hd tudbtd tudbytd

Step-by-step explanation:

fc fcgbtufnyufnutfiygniygmyufniygnyigfntudb rsdut rd utddutestur dutrd uttu uhgugfutfuy8. f utfuy. dutugvu v gigv. uvv gihg ihg igg gv ugv vug ugf ugv ugv v igiugigougojgohgiohgk h. i gigiy gygiygiytiy

angle DAC= angle BAD
what is the length of side bd round to one decimal place

Answers

Answer:

BD ≈ 2.8 units

Step-by-step explanation:

By angle bisector theorem,

"If a segment bisects an angle of a triangle, then it divides the opposite side  into the segments which are proportional to the other two sides"

Here, AD is the bisector of the ∠BAC,

[tex]\frac{BD}{CD}=\frac{AB}{AC}[/tex]

[tex]\frac{8.1}{5.9}= \frac{BD}{2}[/tex]

BD = [tex]\frac{2\times 8.1}{5.9}[/tex]

BD = 2.75

BD ≈ 2.8 units

I NEED HELP ASAP: Figure ABCD is reflected across the x-axis. What are the coordinates of A' , B' , C' , and D' ? Enter your answer by filling in the boxes.

A' ( ___, ___ )
B' ( ___, ___ )
C' ( ___, ___ )
D' ( ___, ___ )

Answers

Answer:

A - 1,4

B -5,8

C -5,4

D -4,2

Step-by-step explanation:

im not shure how to explain

Answer:

A' ( -1, -4 )

B' (-5, -8 )

C' (-5, -4 )

D' ( -4, -2 )

Step-by-step explanation:

I took the test

Find the volume of the cone. Round your answer to the nearest hundredth.

Answers

Answer:

I believe the answer is 1.36

Winston works selling bicycles.
He is paid a flat rate of $200 plus $50 for every bicycle that he sells.
How many bicycles must Winston sell to earn at least $650?

Answers

Answer:

3

Step-by-step explanation:

650/250 = 2.6 (3)can't sell half a cycle

Numerical Response
15b - 6 - 3b + 10
This polynomial simplifies to the form
nb + m
then n + m=?

Answers

Answer:

[tex]\huge\boxed{Answer\hookleftarrow}[/tex]

[tex]15b - 6 - 3b + 10 \\ 15b - 3b - 6 + 10 \\ = 12b + 4[/tex]

12b + 4 is in the form nb + m, where,

n = 12m = 4

So,

[tex] = n + m \\ = 12 + 4 \\ = 16[/tex]

16 is the correct answer.

ʰᵒᵖᵉ ⁱᵗ ʰᵉˡᵖˢ

# ꧁❣ RainbowSalt2²2² ࿐

length of a rectangle is 2 metre and the breadth is 50 find the ratio of a length to the breadth of a rectangle​

Answers

75

explaining
not sure sorry good luck

The probability that Bob and Chris go to the movies is 0.35. The probability that Chris goes to the movies is 0.5. What is the probability that Bob goes to the movies given that Chris goes

Answers

Answer:

[tex]P(B/C)=0.7[/tex]

Step-by-step explanation:

From the question we are told that:

The probability that Bob and Chris go to the movies [tex]P(BnC)= 0.35.[/tex]

The probability that Chris goes to the movies [tex]P(C)= 0.5[/tex]

Generally the equation for the probability that Bob goes to the movies given that Chris goes P(B/C) is mathematically given by

 [tex]P(B/C)=\frac{ P(BnC)}{P(C)}[/tex]

Therefore

 [tex]P(B/C)=\frac{0.35)}{0.5}[/tex]

 [tex]P(B/C)=0.7[/tex]

The mayor is interested in finding a 98% confidence interval for the mean number of pounds of trash per person per week that is generated in the city. The study included 144 residents whose mean number of pounds of trash generated per person per week was 34.5 pounds and the standard deviation was 7.9 pounds. Round answers to 3 decimal places where possible. a. To compute the confidence interval use a

Answers

Answer:

32.966 ; 36.034)

Step-by-step explanation:

Given :

Sample size , n = 144

Mean, x = 34.5

Standard deviation = 7.9

The confidence interval :

Xbar ± Margin of error

Margin of Error = Zcritical * s/√n

Zcritical at 98% = 2.33

Margin of Error = 2.33 * 7.9/√144 = 1.534

Lower boundary = 34.5 - 1.534 = 32.966

Upper boundary = 34.5 + 1.534 = 36.034

(32.966 ; 36.034)

I’m back again :( Please anybody help me

Answers

Welcome back....♡

Surface area = 2( 4 × 2 ) + ( 3 × 4 )

+ 2( 4 × 4 ) + 3( 10 × 4 )

+ 3( 4 × 7 )

Surface area = 16 + 12 + 32 + 120 + 84

Surface area = 264 in^2

how do you prove a theorem?​

Answers

Answer:

Identify the assumptions and goals of the theorem. Understand the implications of each of the assumptions made. Translate them into mathematical definitions if you can. Make an assumption about what you are trying to prove and show that it leads to a proof or a contradiction.

Step-by-step explanation:

Answer:

There are many different ways to go about proving something, discuss 3 methods: direct proof, proof by contradiction, proof by induction. Identify the assumptions and goals of the theorem. Understand the implications of each of the assumptions made. Translate them into mathematical definitions if you can. Make an assumption about what you are trying to prove and show that it leads to a proof or a contradiction

hope this helps

have a good day :)

Step-by-step explanation:

give the other person brainliest pls

Solve the proportion: 144/a = 9/4
a=?

Answers

Step-by-step explanation:

eieueskhdbdjsikskskskjswhwjw

Maya and Zack built the tent below in their backyard how much material did they use to build the tent

Answers

Answer:

[tex]Area = 279ft^2[/tex]

Step-by-step explanation:

Given

See attachment for tent

Required

The material needed

This implies that we calculate the surface area of the tent.

This is calculated as:

Area = 2 * Area of Congruent triangles + 2 * Area of Congruent Rectangles + Area of Base Rectangle

So, we have:

[tex]Area = 2 * \frac{1}{2} * 6 * 8 + 2 * 10.5 * 7 + 10.5 * 8[/tex]

[tex]Area = 48 + 147 + 84[/tex]

[tex]Area = 279ft^2[/tex]

Integrate Sin(3x)Cos(3x) dx

Answers

Answer:

[tex]I = \frac{1}{6}\cdot \sin^{2} 3x + C[/tex]

Where [tex]C[/tex] is the integration constant.

Step-by-step explanation:

We use integration by substitution to obtain the integral, where:

[tex]u = \sin 3x[/tex], [tex]du = 3\cdot \cos 3x\,dx[/tex]

[tex]I = \int {\sin 3x\cdot \cos 3x} \, dx[/tex]

[tex]I = \frac{1}{3} \int {u} \, du[/tex]

[tex]I = \frac{1}{6}\cdot u^{2} + C[/tex]

[tex]I = \frac{1}{6}\cdot \sin^{2} 3x + C[/tex]

Where [tex]C[/tex] is the integration constant.

Jeff and Eric roommates and enjoy talking about sports. They mainly discuss their favorite professional soccer teams. Jeff enjoys European soccer whereas Eric prefers American teams. Outside soccer they do not discuss much. Their lack of range of talking to it fall into which category?​

Answers

Answer:

EXPLANATION:

In each figure below find m∠1 and m∠2, if a||b. Show your work with statements.

====================================

If you have any questions feel free to ask me^^

Have a nice and great day!

Cayler

#PilipinasAngBayanKo

Answer:

Sana Maka help ako tnx

show me an example of fibonacci sequence

Answers

Answer:

See Below

Step-by-step explanation:

The fibonacci sequence is a recursive type sequence where each term is the sum of the two previous terms. The sequence starts out as:

0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765, 10946, 17711, 28657, 46368, 75025, 121393, 196418, 317811...

The fibonacci sequence can be found in nature quite often. For example, it is found in "the fruit sprouts of a pineapple, the flowering of an artichoke, an uncurling fern and the arrangement of a pine cone's bract". It can also be found in the number of tree branches in each row.

Another cool place it can be found is in the diagonals of pascals triangle (shown in the image attached)

*Disclaimer: I do not own any of the images

What’s the answer and how do you figure these out?

Answers

Answer:

140

Step-by-step explanation:

20x+60=30x+20

40=10x

x=4

and

20x+60

20*4+60

=140

A store has a sale with 10% off every item. When you enter the store, you receive a coupon that states that you receive an additional 10% off. Is this equal to a 20% discount

Answers

Answer: It's not equal to 20% discount.

Step-by-step explanation:

Let's assume the cost of a good is $100. Since there's 10% off on every item, the cost of the good will be:

= $100 - (10% × $100)

= $100 - $10

= $90

Since the coupon states that one will receive an additional 10% off, therefore the amount that the person will pay will be:

= $90 - (10% × $90)

= $90 - (0.1 × $90)

= $90 - $9

= $81

If the same good is $100 and there's a 20% discount, the amount that'll be paid will be:

= $100 - (20% × $100)

= $100 - (0.2 × $100)

= $100 - $20

= $80

Therefore, it's not equal to 20% discount.

Please can someone help me I’m confused and lost

Answers

Answer: the answer is the third one

Step-by-step explanation:

well first of all how u get 3is because u have to divide 6 by 2 or u have todo the square root of 6 and 2 and u get 3

Calculate the variance and the standard deviation for the following sample data. Scores: 7, 9, 0, 1, 7, 4, 4, 7, 6

Answers

Answer:

Variance = 9

Standard deviation = 3

Step-by-step explanation:

Step 1

Find the Mean

Means = Sum of values/Number of values

= 0 + 1 + 4 + 4 + 6 + 7 + 7 + 7 + 9/9

= 45/9

= 5

Step 2

The formula for Sample variance

= (x - Mean)²/n - 1

Where

n = number of values = 9

Hence:

Sample variance =

( (0 - 5)² + (1 - 5)²+ (4 - 5)² + (4 - 5)² + (6 - 5)² + (7 - 5)² + (7 - 5)² + (7 - 5)² + (9 - 5)²)/9 - 1

= (-5² + -4²+ -1² + -1² + 1² + 2² + 2² + 2² + 4²) /8

= (25 + 16 + 1 + 1 + 1 + 4 + 4 + 4 + 16)/8

= 72/8

= 9

Sample Standard deviation = √Sample variance

= √9

= 3

PLEASE HELP

A bag hes 10 red marbles, 3 green marbles,
7 yelow marbles, and 5 blue merbles. What is
the probability of crowing a red marble and
then g, blue, marble without replacing the first?

Answers

Answer:

[tex]\frac{3}{5}[/tex]

Step-by-step explanation:

Probability is the chance of an event happening. One finds the probability of an event by using the following general formula,

[tex]\frac{desired}{total}[/tex]

In this case, the desired outcome is pulling whether a red or blue marble from the bag, the desired equals the sum of the number of red and blue marbles.

(red) + (blue)

= 10 + 5

= 15

The total number of marbles is the sum of all the number of marbles in the bag.

(red) + green)  + (yellow) + (blue)

= 10 + 3 + 7 + 5

= 25

Now substitute these values into the formula to find the probability, then simplify,

[tex]\frac{15}{25}[/tex]

Divide both the numerator and denominator by (5),

[tex]\frac{3}{5}[/tex]

While remodeling their living room, the Smart family decided to repaint the walls. They
estimated that they could repaint 55 square feet every half-hour. How many square feet
can they paint per hour?

Answers

Answer:

The Smart family could paint 110 square feet per hour.

Step-by-step explanation:

Given that while remodeling their living room, the Smart family decided to repaint the walls, and they estimated that they could repaint 55 square feet every half-hour, to determine how many square feet can they paint per hour the following calculation must be performed:

1/2 = 0.5

0.5 = 55

1 = X

55 / 0.5 = X

110 = X

Therefore, the Smart family could paint 110 square feet per hour.

A baseball team has won 50 games of 75 played. The team has 45 remaining games to play. How many of the remaining games must a team win in order to win 60% of the total games played during the season?

A. 20
B. 21
C. 22
D. 23

Answers

Answer:

C. 22

Step-by-step explanation:

The team played 75 games and 45 remaining.

75+45=120

60% of 120 = 0.6×120= 72

The team must win 72 games and they already won 50 games so the team has to win 72-50=22 games more.

jill calculates it would take 95 minutes to run 7 miles but it actually take 80 minutes what is percent of error

Answers

Answer:

15.8% = 16%

Step-by-step explanation:

The change (expected result - actual result):

95-80 = 15

Now we divide it by the expected 95 minutes and multiply by 100 to get a percentage.

15/95*100 = 15.8% = 16%

it would be about 16% of error

PLEASEEEEEE IM BEGGING SOMEONE PLEASEEEE HELPPPP PLEASEEEEE PLEASEEEEE SOEMONE HELPPPP PLEASEEEEEEEEEEEEEEEEEEEE​

Answers

Answer:

8 nachos and 5 hot dogs

Step-by-step explanation:

Let x equal number of nachos

let y equal number of how dogs

1.5x + 2y = 22

x + y = 13

y = 13 - x

1.5x + 2(13 - x) = 22

1.5x + 26 - 2x = 22

1.5x - 2x = 22 - 26

-0.5x = - 4

x = -4/-0.5

x = 8

y = 13 - x

y = 13 - 8

y = 5

Find the area of the sector formed by a central angle of 45 degrees in a circle of radius 2.1
meters. Round to the hundredth.

Answers

Answer:

1.731 meters squared

Step-by-step explanation:

Look at the image for reasoning

I need an answer ASAP

Answers

It is the 3rd one your welcome
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