A radioactive substance with initial value of 800g decays according to the exponential model A= 800e^(kt). After 10 years, only 400g of the substance remains. Find the value of k. Round your answer to the nearest thousandth. NO LINKS!!!!
Answer:
k ≈ - 0.069
Step-by-step explanation:
Given
A = 800 [tex]e^{kt}[/tex]
Substitute A = 400 and t = 10 into the equation
400 = 800 [tex]e^{10k}[/tex] ( divide both sides by 800 )
0.5 = [tex]e^{10k}[/tex] ( take the ln of both sides )
ln [tex]e^{10k}[/tex] = ln0.5
10k lne = ln0.5 [ lne = 1 ]
10k = ln 0.5 ( divide both sides by 10 )
k = [tex]\frac{ln0.5}{10}[/tex] ≈ 0.069 ( to the nearest thousandth )
Answer:
Step-by-step explanation:
400 = 800 * e^(k*t)
What are the units of t? I'm taking it as years.
Divide by 800
400/800 = e^(k*10)
1/2 = e^(k*10)
ln(1/2) = ln(e)^(k*10)
ln(1/2) = k*10 * ln(e)
ln(e) = 1
-0.69314 = k*10
-0.069314 = k
Check
A = 800 e^(-0.069314*10)
A = 800 e^(-0.69314)
A = 800 * 0.50000359
A = 400.0028722
Which is close enough to 400
A countries population in 1993 was 253 million. In 1999 it was 237 million. Estimate the population in 2007 using the exponential growth formula. round your answer to the nearest million.
Note: When solving for k, round to four decimal places.
Answer:
240 million
Step-by-step explanation:
I took the application
question in the image
10x -5 = 15
O X = 10
X =-1
x = 2
O X= -2
Answer:
0
Step-by-step explanation:
Anything multiplied by 0 is 0. sorry if i did it wrong
I will go potty now thx
Can someone help! This is due right now and I'm a little confused! Thank you!
Answer:
a) 10 cucumbers
b) two fifth x, or 2/5x
c) 15 vegetables
HELP WITH THIS ASAP!
Answer:
Hi, there your answer will C. 85pi ft^2
Step-by-step explanation:
pi(5)(12)+pi(5)^2
60pi+25pi
85pi ft^2
Hope this helps :)
is 2 a solution to the equation 1/2 x 4 = 5 ?
Answer:
yes it is good luck with your work
Determine the decision criterion for rejecting the null hypothesis in the given hypothesis test; i.e., describe the values of the test statistic that would result in rejection of the null hypothesis. We wish to compare the means of two populations using paired observations. Suppose that d3.125, 2.911, and n8, and that you wish to test the hypothesis below at the 10% level of significance. What decision rule would you use? : 0 against : 0
Answer:
Decision Rule
The critical region for one tailed test with 7 d.f is t > 1.415 for
H0 : ud ≤ 0 against the claim Ha: ud > 0
Step-by-step explanation:
The data given is
Population mean = ud= 0
Sample difference mean = d`= 3.125
Sample difference standard deviation = sd= 2.911
Sample size= n= 8
Formulate the null and alternate hypotheses as
H0 : ud ≤ 0 against the claim Ha: ud>0
The significance level ∝= 0.1
The degrees of freedom = n-1 = 8-1 = 7
The critical region for one tailed test with 7 d.f is t > 1.415
The test statistic is
t= d`- ud/ sd/ √n
Putting the values
t= 3.125-0 / 2.911/√8
t= 3.125/1.0292
t= 3.036
since the calculated value of t falls in the critical region we reject the null hypothesis .
Find the distance of the two given points (1,5) and (4,10)
Answer:
5.831
Step-by-step explanation:
Distance between both given points=Lenght=5.831
2. Use the image to answer the questions.
(a) What is the center and the radius of the circle?
(b) What are the equations of the circle in graphing form and in general form? Show your work.
Answer:
Center = (-1, 1)
Radius = 3
Graphing form
(x + 1)² + (y - 1)² = 3²
General form
x² + y² + 2x - 2y - 7 = 0
Step-by-step explanation:
Center = (-1, 1)
Radius = 3
Graphing form
(x + 1)² + (y - 1)² = 3²
General form \Expand graphing form\
(x² + 2x + 1) + (y² - 2y + 1) - 9 = 0
Rearrange
x² + y² + 2x - 2y - 7 = 0
Qu
Peter hired a cleaning company to clean his house. The cleaning company charges a
fixed fee of $15 plus $17 per hour to clean a house.
a. Write an equation that can be used to determine, c, the total amount in dollars that
the cleaning company charges to clean a house in h hours.
To find the total cost you need to multiply the hourly rate by the number of hours they work and add the fixed fee.
C = 17h + 15
100 POINTS!!!!!! HELP
Question 23
Max and Jay are among 12 contestants in the school spelling bee. If the top two finishers win prizes, what is the probability both Max and Jay will be the two prize winners?
A
1766
B
136
C
166
D
1132
HELP ME PLEASEEEEEEEEEEEEEEEEEEE
Answer:
The second answer choice
Step-by-step explanation:
The pyramid shown is a triangular pyramid. A triangular pyramid consist of 4 faces; 1 triangular base and 3 triangular lateral faces.
Hence, the correct answer would be the second choice.
The number of red tiles in a sack is 5 more than 3 times the number of green tiles in the sack. The
sack contains 35 red tiles, How many green tiles does the sack contain?
Pls help I need this pls help have a good day
A.12
B.10
C.9
D.not here
Answer:
B. 10
Step-by-step explanation:
10 x 3 = 30+5 = 35
question number nine answer
Answer:9
Step-by-step explanation:
Answer:
I think it's either A or D
A bag contains eight white marbles, six red marbles and four blue marbles.
How many blue marbles must be added to the bag so that the probability
of choosing a blue marble is 1/2?
a. 6
b. 5
c. 10
d. 0
Answer:
c) 10
Step-by-step explanation:
you need to add the white and red marbles which would be 14.
then you subtract 14 by the amount of blue marbles.
Giving brainliest ; What is the mean of the data set? {20,1,14,14,9,8} Enter your answer in the box.
Answer:
11
Step-by-step explanation:
(20 + 1 + 14 + 14 + 9 + 8) / 6
= 66 / 6
= 11
A bank is offering 3.5% simple interest on a savings account. If you earned $525 in interest
in 2 years, how much did you deposit in the savings?
O $7,500
O $8,000
O $7.250
$7.000
Answer:
$7500
Step-by-step explanation:
Given
[tex]I = 525[/tex]
[tex]R = 3.5\%[/tex]
[tex]T =2[/tex]
Required
The Principal
This is calculated using:
[tex]I =PRT[/tex]
Make P the subject
[tex]P = \frac{I}{RT}[/tex]
So, we have:
[tex]P = \frac{525}{3.5\% * 2}[/tex]
[tex]P = \frac{525}{7.0\%}[/tex]
[tex]P = 7500[/tex]
write the percent of each figure
that is shaded.
Answer:
1. 21% 2. 70%
Step-by-step explanation:
1. 21 out of 100 are filled in
2. 7/10 are filled in
Hey luvs!
The endpoints of AB are A(1,4) and B(5,-1). What are the coordinates of the point that divides AB in the ratio
2:3?
Answer:
I don't know I'm sorry.............
Please help me. Photo provided
Jovi distributed 3(n+2) and got 3 x n + 3 x 6 is his answer correct
Answer:
Step-by-step explanation:
since 3 is outside the parenthesis (n + 2) you multiply the 3 by the n and the 2 and
3n + 6
next subtract the 6 and add the 6 to the other side
3n - 6 = 6
3n = 6
n = 2
Multiply 4/5 by 10 , and then multiply that product by 17 .
Answer:
your answer is 406.
Step-by-step explanation:
4/5 x 10 will equal to 8. 8 times 17 equals 406.
Which phrase best describes the figure below?
Answer:
B.
Step-by-step explanation:
It only has one base and it's a pentagon. Therefore, it's a pentagonal pyramid.
Find the surface area and volume of the figure. Round to the nearest tenth.
What is the greatest common factor of 12 and 20?
OA) 2
O B) 3
4
D) 6
Answer:
4
Step-by-step explanation:
You can divide both numbers by four and get an even answer
Answer:
4
Step-by-step explanation:
Based on the stated expectations of the sit-and-reach test, which of the following is TRUE?
A.
Men are generally more flexible than women.
B.
Women are generally more flexible than men.
C.
Men and women are about equally flexible.
D.
No broad conclusions can be drawn about flexibility.
Answer:
B
Step-by-step explanation:
How do the angles and side lengths of the preimage relate to the corresponding angles and side lengths of the image of a dilation with a scale factor not equal to 1?
Answer:
The angles are proportional and the side lengths are proportional.
Step-by-step explanation:
Savaas Realize
Can someone help me with this part A: Members of a high school sports team are selling two popular items for a fundraiser:
candy bars and bags of chips. They earn $0.75 for every candy bar they sell and $0.50 for every
Dag of chips. The members want to earn at least $100 from all sales. The members of the sport
team estimate that they won't be able to sell more than 200 units in total.
Part A: Select all the inequalities that model the constraints for this situation, where x
represent the number of candy bars sold and y represent the number of bags of chips.
A. x 20
B. y20
C. x +y s 100
D. x + y < 200
E. 0.75x + 0.50y
100
F. 0.50x + 0.75y > 100
An
Step-by-step explanation:
Cx+y s 100
Answer:
All the inequalities that model the constraints for this situation:
(d) x + y < 200 ;
(e) 0.75 x + 0.50 y ≥ 100
Step-by-step explanation:
What is inequality ?A statement of an order relationship—greater than, greater than or equal to, less than, or less than or equal to—between two numbers or algebraic expressions.
As, x represent the number of candy bars sold & y represent the number of bags of chips sold.
It is given that,
price for one candy bar = $0.75
also, price for one dag of chips = $0.50
So, price for 'x' candy bar = $0.75x
also, price for 'y' of chips = $0.50 y
Is is mentioned in question, the sale of candy bar and bag of chips shoud be atleast $100.
the First ineqaulity be,
0.75 x + 0.50 y ≥100
(which should the sales of candy baar and dag of chips be equal to 100 dollar or greater than 100 dollar)
Now, the second situation
Again, it is mentioned in the question is number of units (candy bar and dag of chips) should be not more than 200 units.
the second inequality be,
x+ y < 200
(which shows that number of candy bar and dag of chips should be less than 200 units.)
All the inequalities that model the constraints for this situation
(d) x + y < 200
(e) 0.75 x + 0.50 y ≥100
Learn more about inequalities here:
https://brainly.com/question/20383699
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