Answer:
0.4435
Step-by-step explanation:
Given that :
X is normally distributed:
mean(m) = 1,000
standard deviation (s) = 250
probability that X lies between 800 and 1,100?
Using the relation :
X = 800
Zscore = (x - m) / s
Zscore = (800 - 1000) / 250
Zscore = - 200 / 250
Zscore = - 0.8
P(Z ≤ - 0.8) = 0.2119
X = 1100
Zscore = (x - m) / s
Zscore = (1100 - 1000) / 250
Zscore = 100 / 250
Zscore = 0.4
P(Z ≤ 0.4) = 0.6554
P(Z ≤ 0.4) - P(Z ≤ - 0.8)
0.6554 - 0.2119
= 0.4435
the half life of c14 is 5730 years. Suppose that wood found at an archeological excavation site contains about 35% as much C14 as does living plant material. Determine when the wood was cut
Answer:
The wood was cut approximately 8679 years ago.
Step-by-step explanation:
At first we assume that examination occured in 2020. The decay of radioactive isotopes are represented by the following ordinary differential equation:
[tex]\frac{dm}{dt} = -\frac{m}{\tau}[/tex] (Eq. 1)
Where:
[tex]\frac{dm}{dt}[/tex] - First derivative of mass in time, measured in miligrams per year.
[tex]\tau[/tex] - Time constant, measured in years.
[tex]m[/tex] - Mass of the radioactive isotope, measured in miligrams.
Now we obtain the solution of this differential equation:
[tex]\int {\frac{dm}{m} } = -\frac{1}{\tau}\int dt[/tex]
[tex]\ln m = -\frac{1}{\tau} + C[/tex]
[tex]m(t) = m_{o}\cdot e^{-\frac{t}{\tau} }[/tex] (Eq. 2)
Where:
[tex]m_{o}[/tex] - Initial mass of isotope, measured in miligrams.
[tex]t[/tex] - Time, measured in years.
And time is cleared within the equation:
[tex]t = -\tau \cdot \ln \left[\frac{m(t)}{m_{o}} \right][/tex]
Then, time constant can be found as a function of half-life:
[tex]\tau = \frac{t_{1/2}}{\ln 2}[/tex] (Eq. 3)
If we know that [tex]t_{1/2} = 5730\,yr[/tex] and [tex]\frac{m(t)}{m_{o}} = 0.35[/tex], then:
[tex]\tau = \frac{5730\,yr}{\ln 2}[/tex]
[tex]\tau \approx 8266.643\,yr[/tex]
[tex]t = -(8266.643\,yr)\cdot \ln 0.35[/tex]
[tex]t \approx 8678.505\,yr[/tex]
The wood was cut approximately 8679 years ago.
When five times a number is decreased by 9, the result is 11. What is the number?
Answer
4
Step-by-step explanation:
Add 9 to 11, then divide that by 5.
Answer:
4
Step-by-step explanation:
work backwards 11+9 is 20. Divide 20 by 5 = 4
Michael exercises more than 35 minutes per day.
Use t to represent Michael's amount of exercise (in minutes per day).
Answer:
t>35
Step-by-step explanation:
Since Michael exercises more than 35 days, t is greater than 35. To express that in an inequality, the answer is t>35. Hope this helped!
If b^2 = 25 then b= Answer it please
Answer:
b = 5
mark me as brainliest plz!! :DD
A newspaper is launching a new advertising campaign in order to increase the number of daily subscribers. The newspaper currently (t0) has 26,000 daily subscribers and management expects that number, S(t), to grow at the rate of subscribers per day, where t is the number of days since the campaign began. How long (to the nearest day) should the campaign last if the newspaper wants the number of daily subscribers to grow to 49,000?
Answer:
57 days
Step-by-step explanation:
Given that:
t(0) = 26000
Growth rate (S'(t)) = 80t^1/2
Targeted number of subscribers = 49000
Take the integral of the growth rate :
∫80t^1/2dt = [(80t^(1/2 + 1)) / 1/2 + 1] + C
[(80t^(1/2 + 1)) / 1/2 + 1] + C = (80t^3/2) / 3/2 + C
(80t^3/2) * 3/2 + C = (160/3)t^3/2 + C
(160/3)t^3/2 + C
Let C = t(0)
(160/3)t^3/2 + 26000 = 49000
(160/3)t^3/2 = 49000 - 26000
(160/3)t^3/2 = 23000
Multiply both sides by 3/160
t^3/2 = 23000* 3/160
t^3/2 = 69000/160
t^3/2 = 431.25
t^(3/2 * 2/3) = 431.25^2/3
t = 57.080277
t = 57 days (approx.)
estimate the answer for 1 2/3 x 5 1/10 (type a whole number
Answer:
Exact Form:
17/2
Decimal Form:
8.5
Mixed Number Form:
8 1/2
Write an equation in the line in slope intercept form
Answer:
Y=2x-1
Step-by-step explanation:
In order to find the slope, its rise over run. So you would move from (0,-1) to the next point it intercepts, (1,1) and find it from there
As for the Y-Intercept, it would just be wherever the line connects with the Y axis, which happens to be (0,-1) or Negative 1.
What number must be added to 101 to produce a number equal to the product of 101 x 21
Answer:
2020
Step-by-step explanation:
101 • 21 = 2121
2121 - 101 = 2020
Simplify (-4/5)divided by (3/-2). -8/15 -6/5 6/5 8/15
Answer:
8/15
Step-by-step explanation:
-4/5 ÷ -3/2
Copy dot flip
-4/5 * -2/3
Multiply the numerators
8
Multiply the denominators
15
Put the numerator over the denominator
8/15
Answer: 8/15
Step-by-step explanation: (-4/5)divided by (3/-2) is 8/15.
Two people start walking at the same time in the same direction. One person walks at 8 mph and the other
person walks at 3 mph. In how many hours will they be 1.25 miles apart?
Answer:
0.25hoursStep-by-step explanation:
Data
speed v1=8mph
speed v2=3mph
distance= 1.25
time t=?
speed= distance/time
distance=speed*time
1.25=8*t-3*t
1.25=8t-3t
1.25=5t
t=1.25/5
t=0.25hours
In minutes it is 15min
Number 10 plzz???????
I need help please thanks
find x when y = 18, if y = 9 when x = 8
ASAP PLEASE
so
y=9 -> y=18
*2
x=8 -> x=16
*2
so x = 16
Answer:
the only logical way solving this question is:
if y=9 then x=8
if y=18 then x should be 16
Step-by-step explanation:
I cant find any other way to solve
Blood pressure: High blood pressure has been identified as a risk factor for heart attacks and strokes. The proportion of U.S. adults with high blood pressure is 0.4. A sample of 39 U.S. adults is chosen. Use the TI-84 Plus Calculator as needed. Round the answer to at least four decimal places. Part: 0 / 60 of 6 Parts Complete Part 1 of 6 Is it appropriate to use the normal approximation to find the probability that more than 43% of the people in the sample have high blood pressure? It ▼(Choose one) appropriate to use the normal curve, since =np ▼(Choose one)10 and =n−1p ▼(Choose one) 10.
Answer:
Yes it appropriate to use the normal approximation to find the probability that more than 43% of the people in the sample have high blood pressure
Step-by-step explanation:
From the question we are told that
The population proportion is p=0.4
The sample size is n = 39
The sample proportion is [tex]\^ p = 0.43[/tex]
Generally for normal approximation to be used
[tex]np > 10[/tex]
so np = 39 * 0.4 = 15.6 > 10
and [tex]n(1- p) > 10[/tex]
so n(1-p ) = 39(1-0.4) = 23.4 >10
Given that the both condition is meet it mean that it appropriate to use the normal approximation to find the probability that more than 43% of the people in the sample have high blood pressure
In a certain state's lottery, 45 balls numbered 1 through 45 are placed in a machine and eight of them are drawn at random. If the eight numbers drawn match the numbers that a player had chosen, the player wins $1,000,000. In this lottery, the order in which the numbers are drawn does not matter.
Compute the probability that you win the million-dollar prize if you purchase a single lottery ticket. Write your answer as a reduced fraction.
P
(win) =
A single lottery ticket costs $2. Compute the Expected Value, to the state, if 10,000 lottery tickets are sold. Round your answer to the nearest dollar.
Answer: $
A single lottery ticket costs $2. Compute the Expected Value, to you, if you purchase 10,000 lottery tickets. Round your answer to the nearest dollar.
Answer: $
Step-by-step explanation:
The order of the numbers doesn't matter, so we'll use combinations instead of permutations. The number of combinations is:
₄₅C₈ = 215,553,195
So the probability of a ticket having the winning combination is 1 / 215,553,195.
The expected value to the state is:
E(X) = 10,000 (1) ($2) + 10,000 (1 / 215,553,195) (-$1,000,000)
E(X) = $19954
The expected value to you is:
E(X) = 10,000 (1) (-$2) + 10,000 (1 / 215,553,195) ($1,000,000)
E(X) = -$19954
You have 8 donuts and you want to give 1/4 of them to a friend. How many donuts would your friend get?
Answer: pretty sure the friend would get 2 donuts
Step-by-step explanation:
If a roof has a pitch of 5 to 11, how high will the roof rise over a 33-foot run?
a.
3
C.
2
72 feet
1 feet
b. 15 feet
d.
20 feet
The answer is b. 15ft
I thought of a two-digit number. The unit digit of my number is 7 more than the tens digit cubed. What is my number?
Answer:
18
Step-by-step explanation:
The tens digit a is cubed (a³ ) still less than the biggest possible 1 -digit number . It can be only 0 or 1 , so even 2³ =8 ( in such case the unit digit is 15,- that's not possible) .
0 can not be the the first digit in 2 digit number. So the only possible tens digit is 1. So the unit number is 1+7=8.
Answer 18
Answer:
18
Step-by-step explanation:
anyone in flvs? we should find each other in live lessons lol
Answer:
nope
Step-by-step explanation:
X+ 2 = 5 and y-3 = 2
Answer:
x=3
y=5
because 5-2=3 so 3 is x
and 2+3 is 5 so y is 5
Answer:
X = 3, Y =
Step-by-step explanation:
This is because 2+3=5,
and5-3=2
SOMEONE PLEASE HELP ILL GIVE BRAINLIEST
Answer:
A.
Step-by-step explanation:
Toby works at an amusement park. He loads 10 new passengers onto the roller coaster every
3/4
of a minute. At what rate does Toby load passengers?
Pleaseeee
Answer:
13 1/3
Step-by-step explanation:
im sure this is right btw
7th grade math help me plzzzz
Answer:
a. -14
b. -13
c. -5
d. -3
e. -12
f. 0
Step-by-step explanation:
hope it helps
Answer:
A is -14.
B is -13
C is -5
D is -3
E is -12
F is 0
Step-by-step explanation:
A, B, E both numbers are negative so you just add them together and add a negative sign.
C would read 4-9
D 10-7 and add a - to the answer
F is 6-6
QUICK
solve this equation
a^n+b^n=
Its late and i need this pls
Gretchen made a paper cone to hold a gift for a friend. The paper cone was 11 inches high and had a radius of 4 inches. Find the volume of the paper cone to the nearest tenth. Use 3.14 for π.
The volume is ___in^3
Answer:
184.2 in^3
Step-by-step explanation:
vol of cone=
[tex]\pi {r}^{2} \frac{h}{3} [/tex]
[tex]3.14 \times 16 \times \frac{11}{3} [/tex]
=184.2
A gallon of gas costs an average of two dollars is Betty spends $144 a month on gas determine how many gallons of gas she uses a month
Answer:
she uses 72 gallons
Step-by-step explanation:
just do 144/2 and the answer is 72
if you wanna check your answer just do 72x2 and it equals 144
I need help nowwwwww !!!!!????
you should just have to times the yards by three like the second one is 12
find the sum of 2x ÷ x-1 and x÷x-1
Answer with step-by-step explanation:
First of all, ORDER OF OPERATIONS!! 2x/x is 2/1, which is 2. Then, subtract 1, which is 1.
2x ÷ x - 1 = 1
Same thing: x/x = 1. Subtract 1 from 1, which is 0.
x ÷ x - 1 = 0
1 + 0 = 1
Hope this helped!
Translate the sentence into an equation.
Seven times the sum of a number and 2 is 6.
Use the variable y for the unknown number.
Answer:
7(y+2)=6
Step-by-step explanation:
its right
I need help the instructions say go left to right
Calculate.
(2x105)(4.3x109)
Write your answer in scientific notation.
Answer:
9.8427x10⁴
Step-by-step explanation:
Answer:
98427x^2
9.8427x10^4
Step-by-step explanation: