Answer:
A He should ask his students to know what they prefer
Step-by-step explanation:
The half-life of a radioactive substance is the time it takes for a quantity of the substance to decay to half of the initial amount. The half-life of the radioactive gas radon is approximately 2.8 days. The initial amount of radon used in an experiment is 74 grams. If N represents the number of grams of radon remaining t days after the start of the experiment,
a. Write an equation that gives Nin terms of t.
b. how much gas radon approximately remains after 2.8 days?
c. approximately when will the amount of radon remaining be 10 grams?
Step-by-step walkthrough:
a.
Well a standard half-life equation looks like this.
[tex]N = N_0 * (\frac{1}{2})^{t/p[/tex]
[tex]N_0[/tex] is the starting amount of parent element.
[tex]N[/tex] is the end amount of parent element
[tex]t[/tex] is the time elapsed
[tex]p[/tex] is a half-life decay period
We know that the starting amount is 74g, and the period for a half-life is 2.8 days.
Therefore you can create a function based off of the original equation, just sub in the values you already know.
[tex]N(t) = 74g * (\frac{1}{2})^{t/2.8days[/tex]
b.
This is easy now that we have already made the function. Here we just reuse it, but plug in 2.8 days.
[tex]N(t) = 74g * (\frac{1}{2})^{t/2.8days} = N(2.8days) = 74g * (\frac{1}{2})^{2.8days/2.8days}\\= 74g * \frac{1}{2} = 37g[/tex]
c.
Now we just gotta do some algebra. Use the original function but this time, replace [tex]N(t)[/tex] with 10g and solve algebraically.
[tex]10g = 74g * (\frac{1}{2})^{t/2.8days}\\\\\frac{10g}{74g} = (\frac{1}{2})^{t/2.8days}[/tex]
Take the log of both sides.
[tex]log(\frac{5}{37}) = log((\frac{1}{2})^{t/2.8days})[/tex]
Use the exponent rule for log laws that, [tex]log(b^x) = x*log(b)[/tex]
[tex]log(\frac{5}{37}) = \frac{t}{2.8days} * log(\frac{1}{2})[/tex]
[tex]\frac{log(\frac{5}{37})}{log(\frac{1}{2})} = \frac{t}{2.8days}[/tex]
[tex]2.8 * \frac{log(\frac{5}{37})}{log(\frac{1}{2})} = t[/tex]
slap that in your calculator and you get
[tex]t = 8.1 days[/tex]
The first two terms of an arithmetic sequence are 7 and 11. Which of the following is the value
of its 30th term
Answer:
123
Step-by-step explanation:
Add 4 enough times to 11 and you will get there.
the current value of an item is 300000 at tge beginning of the year ,of its value at the end of every year is ¾ of the value at the beginning of the year find its value after 5 years
Answer:
71191.4 to the nearest tenth.
Step-by-step explanation:
Value after 5 years = 300000(3/4)^5
= 71191.41
(True/False) In an experimental study, participants are randomly allocated (by chance, rather than by choice), to two different experimental groups. The reason for randonmization is to reduce bias.
Answer:
TRUE
Step-by-step explanation:
The regular octagon shown is enlarged so that its side are 3 times
as large. What affect does this have on the perimeter?
Answer:
The perimeter is 2 times greater.
Step-by-step explanation:
Solve by completing the Square
[tex]2x^{2} +3x=20[/tex]
Step-by-step explanation:
2x²+3x=20
2x²+3x=20
(√2x)²+2(√2x)(3/2√2)+(3/2√2)²-(3/2√2)²=20
(√2x+3/2√2)²=20+9/8
(√2x+3/2√2)²= 169/8
(√2x+3/2√2)= ±13/2√2
√2x=10/2√2 or -16/2√2
x= 10/4 or -16/4
x= 5/2 or -4
The table displays the scores of students on a recent exam. Find the mean of the scores to the nearest ioth. Score Number of Students 55 8 60 6 65 3 70 4 75 9 80 3 85 3 90 4
Answer:
38.75
Step-by-step explanation:
Not sure what you mean by ioth but when you add up all the numbers and divide by n, you get 38.75 (hopefully you can round it to whatever you want)
Select the set of equations that is NOT equivalent to 8k = 20
help, asap, explain, thx
a^2-b^2=8
a+2=2
then a-b=?
Step-by-step explanation:
a + 2 = 2
a = 2 - 2
a = 0
a² - b² = 8
0 - b² = 8
b² = -8
This question is impossible.
What is the volume of the square pyramid?
Answer:
v = 118.333333333
Step-by-step explanation:
formula: V=a^2h/3
The area is the base edge (so 5)
The height is the line going up the triangle (14.2)
Fill in:
v = 5^2(14.2/3)
Solve:
exponent first: 5^2 = 25
v = 25 (14.2/3)
divide/find out fraction: 14.2/3 = 4.73333333333
v = 23 x 4.73333333333
multiply: 23 x 4.73333333333 = 118.333333333
v = 118.333333333
you can also write as v = 118.3 with a line like “-“ over 3 to show the 3 is repeating:)
i need to find the volume of a cylinder and the radius is 10 cm and height is 8 cm
Answer:
2513.27
Step-by-step explanation:
V=πr^2h=π·102·8≈2513.27412
Find The Square Root Of
[tex] \frac{144}{169 } [/tex]
[tex]===============================[/tex]
Let's find the square root of
[tex]\bold{\displaystyle\frac{144}{169}}[/tex]
So what number times itself equals [tex]\bf{\displaystyle\frac{144}{169}}[/tex]?
Take the square root of both the numerator (144) and the denominator (169)
[tex]\bold{\sqrt{\displaystyle\frac{144}{169} }}[/tex]
The square root of 144 is 12 (12 times itself equals 144), and the square root of 169 is 13 (13 times itself equals 169)
[tex]\bold{\displaystyle\frac{12}{13}}[/tex]
This number times itself equals [tex]\bf{\displaystyle\frac{144}{169}}[/tex].
[tex]==================================[/tex]
Notes:Hope everything is clear.Let me know if you have any questions!Enjoy your day!#KnowledgeIsPowerYou can easily find the square root of a number by entering the number you want to find the square root of and pressing the [tex]\sqrt{x}[/tex] button on your calculator, or just remembering the basic numbers, like "12×12 (12²=144) :-)Answered by:
[tex]^\star^\bigstar^\circ\tt{An~Emotional~Helper!~:D}}^\circ^\bigstar[/tex]
The unit rate of change of y with respect to r is the amount y changes for a change of one unit in I.
is the unit rate of change of y with respect to r greater in the equation y = 0.25% or in the graph below?
Choose 1 answer:
The graph
The unit rates are the same.
The equation
Answer:
(.8-.4)/(2-1) =.4
SLOPE IS THE RATE OF CHANGE Answer: A
Step-by-step explanation:
HELP ASAP ILL MARK BRAINLIST
Describe the tangent ratio and solve. Show your work. Round your answer to the nearest thousandth.
Answer: 0.428
Step-by-step explanation:
[tex]\tan \theta=\frac{\text { side opposite to } \theta}{\text { side adjacent to } \theta}[/tex]
[tex]\begin{aligned}\tan \theta &=\frac{A B}{A C} \\\tan \theta &=\frac{6}{14} \\\tan \theta &=\mathbf{0 . 4 2 8}\end{aligned}[/tex]
PLEASE HELP!!
Instructions: Find the value of the trigonometric ratio. Make sure to simplify the fraction if needed.
Answer:
40/41.
Step-by-step explanation:
sin Z = opposite side / hypotenuse
= 40/41
You+deposit+$500+in+an+account+that+pays+5%+interest+compounded+yearly. +how+much+money+is+in+the+account+after+4+years?
[tex]~~~~~~ \textit{Compound Interest Earned Amount} \\\\ A=P\left(1+\frac{r}{n}\right)^{nt} \quad \begin{cases} A=\textit{accumulated amount}\\ P=\textit{original amount deposited}\dotfill &\$500\\ r=rate\to 5\%\to \frac{5}{100}\dotfill &0.05\\ n= \begin{array}{llll} \textit{times it compounds per year}\\ \textit{yearly, thus once} \end{array}\dotfill &1\\ t=years\dotfill &4 \end{cases} \\\\\\ A=500\left(1+\frac{0.05}{1}\right)^{1\cdot 4}\implies A=500(1.05)^4\implies A\approx 607.75[/tex]
The final amount will be $607.75 after 4 years if the principal amount is $500 and it compounded annually with interest rate of 5%
What is compound interest?It is defined as the interest on the principal value or deposit and the interest which is gained on the principal value in the previous year.
We can calculate the compound interest using the below formula:
[tex]\rm A = P(1+r)^t[/tex]
Where A = Final amount
P = Principal amount
r = annual rate of interest
n = how many times interest is compounded per year
t = How long the money is deposited or borrowed (in years)
We have in the problem:
P = $500, r = 5% = 0.05, and n = 4 years
[tex]\rm A = 500(1+0.05)^4[/tex]
A = $607.75
Thus, the final amount will be $607.75 after 4 years if the principal amount is $500 and it compounded annually with interest rate of 5%
Learn more about the compound interesthere here:
brainly.com/question/26457073
#SPJ4
Number 3. (Look at the Image) Using the formula ū = ||T||(cos o 7 + sin 0 j) Il, find the magnitude and direction of ū= (3,-V3).
Magnitude should be written in simplified radical form.
ů= 11 ull (cosoit sin 63
ů
find magnitude and direction of
ů - <333)
Answer:
its 54
Step-by-step explanation:
1+2=3 3x5=15 15x2=30 30+16=46 46+8=54
Find the area of a triangle
Answer:
240 feet
Step-by-step explanation:
The formula for finding the area of a triangle is: [tex]\frac{1}{2}bh[/tex], where [tex]b[/tex] stands for the base and [tex]h[/tex] stands for the height.
In this case, 20 is our height, and 24 is our base. Let's plug that into the formula.
[tex]1/2(20)(24)\\1/2(480)\\240[/tex]
Therefore, the area of the triangle is 240 feet.
#LearnWithBrainly
PLEASE HELP
A shipping container is in the shape of a right rectangular prism with a length of 8. 5
feet, a width of 4 feet, and a height of 7 feet. The container is completely filled with
contents that weigh, on average, 0. 85 pound per cubic foot. What is the weight of the
contents in the container, to the nearest pound?
Answer:
14.875
Step-by-step explanation:
hope it helped
whats 1+1 first answer i will vote brainlyest
Answer:
2
Step-by-step explanation:
Yessir
Pls help me: A couple plans to have 4 children. The gender of each child is equally likely. Design a simulation involving 90 trials that you can use to model the genders of the children, you do not need to generate the numbers or find the probability, just explain how your simulation would work. You should include information like how many digits long each number is, which digits represent a boy child and which digits represent a girl. also show the step by step of how to ans this.
The simulation of the gender of a child by the couple is an illustration of probability.
How to design a simulation?The number of trials (n) is given as:
n = 90
The chance of getting each gender is equal.
So, we have:
P(Boy) = 0.5
P(Girl) = 0.5
The simulation would be based on numbers 0 to 9. Such that:
The numbers 0 to 4 represent a boy childThe numbers 5 to 9 represent a girl childNotice that each gender have the same amount of digits i.e. 5
This is so because they both have equal chance
Read more about probability at:
brainly.com/question/251701
HALP PLSSSSSSSS will give brainliset
Answer:
ezz multiply and see what it s if its wrong then txt me
Step-by-step explanation:
Order of operations 5-2(5-27)+5
The answer to your question would be 54
Work Shown:
5-2(5-27+5
Calculate with parenthesis (5-27): -22
5-2(-22)+5
Multiply and divide (left to right) 2(-22): -44
5-(-44)+5
Add and subtract (left to right) 5-(-44)+5
54
Shawna won 40 super bouncy balls playing
horseshoes at the county fair. At school she
gave three to every student in her math
class. She only has 1 remaining. How
many students are in her class?
Answer:
13 not including Shawna
Step-by-step explanation:
First, you have to take into account that the remainder is 1, so you must subtract 1 from 40, giving you 39. 39/3 is 13, so 13 is your final answer.
Answer:
13
Step-by-step explanation:
13 x 3=39. There is one remaing, +1 = 40.
28 is increased by 150%. what's the final number
Answer:
70
Step-by-step explanation:
20x(1+150%)
28x(1+1.5)
28x2.5
70
Bag A contains 5x coins.
Bag B contains 3x coins.
8 coins are taken from Bag B and put into Bag A
The ratio of coins in Bag A to Bag B is now 11:5
Work out the total number of coins.
Answer:
given ,
number of coins in bag A = 5x
number of coins in bag B = 3x
_____________________________________
According to Question ,
8 coins are taken from Bag B and put into Bag A
The ratio of coins in Bag A to Bag B is now 11 : 5
therefore ,
[tex] \frac{5x + 8}{3x - 8} = \frac{11}{5} \\ \\ 5(5x + 8) = 11(3x - 8) \\ \\ 25x + 40 = 33x - 88 \\ \\ 33x - 25x = 40 + 88 \\ \\ 8x = 128 \\ \\ x = \cancel\frac{128}{8} \\ \\ \fbox{x =16} [/tex]
now ,
[tex]no. \: of \: coins \: in \: bag \: A = 5x \\ \dashrightarrow{5 \times 16 = 80 \: coins}[/tex]
[tex]number \: of \: coins \: in \: bag \: B = 3x \\ \dashrightarrow{3 \times 16 = 48 \: coins}[/tex]
[tex]total \: number \: of \:coins = 80 + 48 \\ \dashrightarrow{ 128 \: coins}[/tex]
hope helpful :D
PLS HELP ASAP THANKS ILL GIVE BRAINLKEST PLS THANKS PLS THANKSS
Answer:357.96in
Step-by-step explanation:
1. Surface area of a cylindar is A= 2πr(r+h)
2. A= 2·π·3 (3+16)
Second question
Answer: 296in
A 2,000 piece puzzle is in the shape of a trapezoid. The lengths of the bases are 7012 and 6512 inches long. The area of the puzzle is 1,224 square inches. What is the height of the puzzle?
in.
Answer:
0.18
Step-by-step explanation:
Maths big brain
In a certain area of a large city, it is hypothesized that 40 percent of the houses are in a dilapidated condition. A random sample of 75 houses from this section and 90 houses from another section yielded a difference of 0.09. If there is no difference between the two areas in the proportion of dilapidated houses, what is the probability of observing a difference this large or larger?
Using the normal distribution and the central limit theorem, it is found that there is a 0.24 = 24% probability of observing a difference this large or larger.
Normal Probability DistributionIn 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]
It measures how many standard deviations the measure is from the mean. After finding the z-score, we look at the z-score table and find the p-value associated with this z-score, which is the percentile of X.By the Central Limit Theorem, for a proportion p in a sample of size n, the sampling distribution of sample proportion is approximately normal with mean [tex]\mu = p[/tex] and standard deviation [tex]s = \sqrt{\frac{p(1 - p)}{n}}[/tex], as long as [tex]np \geq 10[/tex] and [tex]n(1 - p) \geq 10[/tex].When two variables are subtracted, the mean is the subtraction of the means, while the standard deviation is the square root of the sum of the variances.In this problem, for each sample, the mean and standard error are given by:
[tex]\mu_I = 0.4, s_I = \sqrt{\frac{0.4(0.6)}{75}} = 0.0566[/tex]
[tex]\mu_{II} = 0.4, s_{II} = \sqrt{\frac{0.4(0.6)}{90}} = 0.0516[/tex]
Hence, for the distribution of differences, the mean and the standard error are given by:
[tex]\mu = \mu_I - \mu_{II} = 0.4 - 0.4 = 0[/tex]
[tex]s = \sqrt{s_I^2 + s_{II}^2} = \sqrt{0.0566^2 + 0.0516^2} = 0.0766[/tex]
The probability of observing a difference this large or larger is given by P(|Z| > Zx), in which Zx is the z-score when X = 0.0766. Hence:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
By the Central Limit Theorem:
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]Z = \frac{0.09 - 0}{0.0766}[/tex]
Z = 1.175.
Hence the probability is P(|Z| > 1.175), which is 2 multiplied by the p-value of Z = -1.175. Then:
2 x 0.12 = 0.24.
0.24 = 24% probability of observing a difference this large or larger.
To learn more about the normal distribution and the central limit theorem, you can check https://brainly.com/question/24663213
Help ASAP I am so confuseddd
Answer:
radius = 9.5 cm
Step-by-step explanation:
If 2 chords intersect then the product of the parts of 1 chord is equal to the product of the parts of the other chord, that is
PT × TQ = ST × TR
PT × 3 = 4 × 12 = 48
3 PT = 48 ( divide both sides by 3 )
PT = 16
then
diameter = PT + TQ = 16 + 3 = 19 cm
radius = 19 ÷ 2 = 9.5 cm