Answer:
6.38548 years
Step-by-step explanation:
1 = 2 [tex]e^{42k}[/tex]
1/2 = [tex]e^{42k}[/tex]
ln(1/2) = 42k ln(e)
ln(1/2)/42 = k
k = -0.01650
~~~~~~~~~~~~~~
45 = 50 [tex]e^{-0.01650t}[/tex]
45/50 = [tex]e^{-0.01650t}[/tex]
ln(45/50) = -0.01650 t ln(e)
ln(45/50)/ -0.01650 = t
t = 6.38548 years
The number of years for the radioactive element to reach a mass of 45 grams is given by t = 6.384129 years
What is half-life of an element?The half-life of a radioactive isotope is the amount of time it takes for one-half of the radioactive isotope to decay. The half-life of a specific radioactive isotope is constant; it is unaffected by conditions and is independent of the initial amount of that isotope.
Half-life (symbol t½) is the time required for a quantity (of substance) to reduce to half of its initial value
The decay constant λ is = 0.693/t½
where t½ is the half-life of the element
Given data ,
Let the number of years be t
Let the initial mass of the element be a = 50 grams
The final mass of the element be ( a - x ) = 45 grams
Now , Element X is a radioactive isotope such that every 42 years, its mass decreases by half
And , half life t½ = 42 years
So , the decay constant k = 0.693/t½
k = 0.693 / ( 42 )
k = 0.0165
And , k= 2.303/t {log (a/a-x)}
So , t = 2.303 / ( 0.0165 ) log ( 50/45 )
On simplifying , we get
t = 6.384129 years
Hence , the number of years for the radioactive element to reach 45 grams is 6.384129 years
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What is the simplest shape in Mathematics?
A survey asked 60 students if they play an instrument and if they are in band.
1.35 students play an instrument.
2. 30 students are in band.
3. 30 students are not in band.
Which table shows these data correctly entered in a two-way frequency table?
=======================================================
Explanation:
The table headers will look like choice A or choice C. Notice that we have simple yes or no questions along either the row or column labels; also, the labels are consistent. Choice B can be ruled out because the labels aren't consistent (or don't match up). Choice D is overcomplicated so it can be ruled out also.
We're told that 35 students play an instrument. That means 35 goes at the end of the "plays instrument" row, in the "total" column.
This is enough to see that choice A is the final answer
Furthermore, 30 students are in a band. So we have "30" at the bottom of the "band" column, and in the "total" row. The same applies to the 30 people not in band.
(solving rate problems). Michelle can
complete a
landscaping job in 6
days and Danielle
can complete the
same job in 4 days.
Working together, in
how many days
could they complete
the job
They could complete the job together in 2.4 days
The known parameters are;
The number of days it would take Michelle to complete the landscaping job = 6 days
The number of days it would take Danielle to complete the landscaping job = 4 days
The unknown parameter;
The number of days can the job be completed if they work together
The process of finding the solution;
The rate at which Michelle works = 1/6 of the landscaping work per day
The rate at which Danielle works = 1/4 of the landscaping work per day
Method;
Find their combined work rate, from which the time would take them to complete the job together can be found
Let, C, represent their combined work rate
Therefore, we have;
C = (1/6 + 1/4) = 5/12 of the landscaping (work) job/(per) day
The number of days they could complete the, 1, job = 1 job(work)/(5/12 (work)job/day) = 12/5 days = 2.4 days
∴ The number of days they could complete the job together = 2.4 days.
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SIN TRIG PLEASE HELP 50 POINTS
If sin y° = s/8 and tan y° = s/t what is the value of sec y°
a. sec y° = 8s
b. sec y° = 8t
c. sec y° = 8/t
d. sec y° = t/8
Answer:
C
Step-by-step explanation:
We are given that:
[tex]\displaystyle \sin y^\circ = \frac{s}{8}\text{ and } \tan y^\circ = \frac{s}{t}[/tex]
And we want to find the value of:
[tex]\displaystyle \sec y^\circ[/tex]
Recall that tan(θ) = sin(θ) / cos(θ). Since sec(θ) = 1 / cos(θ), tan(θ) = sin(θ)sec(θ). Substitute:
[tex]\displaystyle \sin y^\circ \sec y^\circ = \frac{s}{t}[/tex]
Substitute:
[tex]\displaystyle \frac{s}{8}\sec y^\circ =\frac{s}{t}[/tex]
Solve for secant:
[tex]\displaystyle \sec y^\circ = \frac{8}{t}[/tex]
Hence, our answer is C.
Answer:
c. sec y° = 8/t
Step-by-step explanation:
I took the test
Find the missing segment in the image below
Answer:
10/2=15/?
Step-by-step explanation:
I can help you to your all question but it need time. I have to write short.
?=3
What is the division? 9÷890
Answer:
98.89
Step-by-step explanation:
Answer: 9/890=0.01011235955
Step-by-step explanation:
HELP PLS IM FAILING PYTHAGOREAN THEOREM
Answer: 4.6 km
Step-by-step explanation:
a^1 + b^2 = c^2
2^2 + b^2 = 5^2
4 + b^2 = 25
b = sqrt 25 - 4
b = sqrt 21 = 4.6 km
Determine which equations have the same solution set as 2/3 -x +1/6 = 6x by recognizing properties, rather than solving. Check all that apply.
Answer:
The answer is "0.1190".
Step-by-step explanation:
Given:
[tex]\to \frac{2}{3} -x +\frac{1}{6} = 6x\\\\\to \frac{2}{3} +\frac{1}{6} = 6x+x\\\\\to \frac{4+1}{6} = 7x\\\\\to \frac{5}{6} = 7x\\\\\to x=\frac{5}{6\times 7} \\\\\to x=\frac{5}{42}\\ \\\to x= 0.1190[/tex]
Answer:
A.) 4 - 6x + 1 = 36x
B.) 5/6 - x = 6x
F.) 5 = 42x
Step-by-step explanation:
edge.
Jim removed 27 gallons of water from a rainwater storage tank. There are 59 gallons left in the tank. What equation can Jim use to find how much water was in the tank earlier? Use x to represent the amount of water originally in the tank.
Answer: X = 86 gallons
Step-by-step explanation:
X-27=59
X=59+27
hello! HELP NEEEDED!!!!!!!!!!!
Answer:
$2.50
Step-by-step explanation:
Sally pays 2.5 lbs of chuck for 6.25. We need to convert this to 1 pound, to see how much money it take to equal 1 pound .
Set up proportion.
[tex] \frac{1}{x} = \frac{2.5}{6.25} [/tex]
[tex]2.5 x = 6.25[/tex]
[tex]x = 2.5[/tex]
it takes 2 dollar and 50 cents for 1 lb of ground chuck
Answer:
$2.50
Step-by-step explanation:
In my theory, I suppose that the key word to look at is "per"in the question above. All you need to do is to is to divide $6.25 with 2 1/2 lb
Identify the sequence that lists the sides of △MNO in order from shortest to longest.
Answer:
MO, NO, MN
Step-by-step explanation:
First, we can identify this triangle as a right triangle, as given by the square next to the O. Next, we know that a right angle is equal to 90 degrees, and the sum of the angles of a triangle is equal to 180 degrees.
Therefore,
∠M + ∠O + ∠N (the angles of the triangle) = 180
49 + 90 + ∠N = 180
139 + ∠N = 180
subtract both sides by 139 to isolate the variable
∠N = 41
Therefore, ∠N is 41 degrees.
In a triangle, given the angles, we know that the side opposite the smallest angle is the side with the smallest length and so on.
Our angle lengths are
41, 49, and 90 degrees in order.
Therefore, the side opposite the largest angle (90 degrees, or ∠O) is the longest side. This is MN. Similarly, ∠N is the smallest angle, and the side opposite of that (MO) is the shortest side. This leaves NO to be in the middle
If ? A² + b² = 7b and b² + (2b-a) ²= 7², what is (a - b) ²?
Answer:
7^2+2ab - 4b^2
Step-by-step explanation:
A² + b² = 7b
b² + (2b-a) ²= 7²
FOIL
b^2 +4b^2-4ba+a^2= 7^2
Rewriting
a^2 -2ab + b^2 +4b^2 -2ab = 7^2
Add 2ab and subtract 4b^2 from each side
a^2 -2ab + b^2 +4b^2 - 4b^2 -2ab+2ab = 7^2+2ab - 4b^2
a^2 -2ab + b^2 = 7^2+2ab - 4b^2
(a-b)^2 = 7^2+2ab - 4b^2
Find the length of BW
Answer:
[tex]BW \approx 132.589[/tex]
Step-by-step explanation:
The given triangle (BWS) is a right triangle. This is indicated by the box around one of its angles, signifying that it is a right angle. One property of a right triangle is the right angle trigonometric ratios. These are a set of ratios that can be used to describe the relationship between the sides and angles in a triangle. These ratios are as follows:
[tex]sin(\theta) = \frac{opposite}{hypotenuse}\\\\cos(\theta)=\frac{adjacent}{hypotenuse}\\\\tan(\theta)=\frac{opposite}{adjacent}[/tex]
Please note that the (opposite) and (adjacent) sides are subjective, the sides that are named these terms depend on the angle of reference. However the term (hypotenuse) refers to the sides opposite the right angle of a right triangle, this term is the same no matter the angle used in the ratio.
In this case, one is given the length of the side (SB) and the measure of angle (<W), one is asked to find the length of the side (BW). The best ratio to use in this case is the ratio tangent (tan).
[tex]tan(\theta)=\frac{opposite}{adjacent}[/tex]
Substitute,
[tex]tan(9)=\frac{21}{adjacent}[/tex]
Inverse operations,
[tex]tan(9)=\frac{21}{adjacent}[/tex]
[tex]adjacent=\frac{21}{(tan(9))}[/tex]
[tex]adjacent\approx132.688782[/tex]
[tex]BW \approx 132.589[/tex]
In 2010, 1 Canadian dollar cost .56 British pounds and in 2012 it cost .63 British pounds. How much would 1 British pound purchase in Canadian dollars in 2010 and 2012? 2010: 1.78 dollars, 2012: 1.57 dollars 2010: 1.79 dollars, 2012: 1.59 dollars 2010: 1.87 dollars, 2012: 1.65 dollars 2010: 1.97 dollars, 2012: 1.75 dollars
Answer:
2010: 1.79 dollars, 2012: 1.59 dollars
Step-by-step explanation:
In 2010,
1 Canadian dollar = .56 British pounds.
We want to find how many pounds go into a dollar, so we somehow have to make the equation equal to 1 pound. To do this, we can multiply the amount of pounds by its reciprocal to equal 1. To find the reciprocal of a number, we simply divide 1 by it. For .56, this is (1/.56). Therefore, we can multiply both sides by (1/.56) to get
1.79 Canadian dollars = 1 British pound
Similarly, for 2012, we have 1 dollar = .63 pounds. Multiplying both sides by 1/.63, we get
1.59 Canadian dollars = 1 British pound
HEEEEEEEEEEEEEEEEEEELP
Answer:
2 miles per hour
Step-by-step explanation:
To find her walking pace in 'miles per hour' we need to divide the distance (in miles) by the time (in hours).
Speed = Distance/ Time
The time is given in minutes , but 50 minutes = 50/60 hours
=5/6 hours
1 2/3 ÷ 5/6
=5/3 × 6/5 miles per hour
Now cut it
= 2 miles per hour
The function m is given in three equivalent forms.
Which form most quickly reveals the zeros (or "roots") of the function?
Choose 1 answer:
m(x) = 2(x +4)^2 – 8
m(x)= 2x^2 + 16x + 24
m(x)=2(x+6)(x+2)
Write one of the zeros
Find the area of this circle. Use 3 for .
A = r2
12 cm
[?] cm2
Answer:
452.16 cm²
Step-by-step explanation:
Given :-
Radius = 12cm .To find :-
Area of circle .Solution :-
As we know that ,
A = πr² A = 3.14 * (12 cm)² A = 3.14 * 144cm² A = 452.16 cm²Step-by-step explanation:
[tex]area = \pi {r}^{2} \\ = \pi \times {12}^{2} \\ = \pi \times 144 \\ = 3.14 \times 144 \\ = 452.16 {cm}^{2} \\ thank \: you[/tex]
In a sports club of 150 members, 88 play golf, 63 play bowls, and 45 play golf and bowls. Find the probability that:
a) a member plays golf only.
b) a member doesn't play golf or bowls.
pls explain too if u could. thanks!
Answer:
a) .287
b) .293
Step-by-step explanation:
The answers are boxed in red in the picture.
First I found how many people only golfed. Then I did the same for the people that only bowled. Next I found how many members didn't golf or bowl.
From there I found the probabilities by dividing
a.) # of members that only golf / total # of members
b.) # of members that don't bowl or golf / total # of members
"A parabola has the equation y=3x^2+ 6x- 12 . What are the coordinates of the vertex? (You must solve by factoring)!!!!!" I NEED THE ANSWER TO THIS FAST WITH STEPS I'm a grade 10 academic student by the way
enjoy it
it best answer for you
A chef cooked 7kg of mashed potatoes for a banquet. If guests only ate 3/4 of the amount he cooked, how much of the potatoes were eaten?
Answer:
5.25 kg of the mashed potatoes were eaten.
Step-by-step explanation:
(3/4) * 7 = 5.25
I hope this is helpful :)
Solve the following for the value of the pro-numeral:
(c - 7) / 2 = -5
Answer:
[tex] \frac{(c - 7)}{2} = - 5 \\ c - 7 = - 5 \times 2 \\ c - 7 = - 10 \\ c = - 10 + 7 \\ c = - 3[/tex]
I hope I helped you^_^
Defenation of time, distance and speed
A steep mountain is inclined 75 degree to the horizontal and rises 3900 ft above the surrounding plain. A cable car is to be installed by connecting a cable from the top of the mountain to a spot on the plain that is 910 ft from the base of the mountain. Find the shortest length of cable needed.
Answer: [tex]4004.76\ ft[/tex]
Step-by-step explanation:
Given
inclination is [tex]\theta=75^{\circ}[/tex]
Mountain is [tex]h=3900\ ft[/tex] high
Cable is tied [tex]x=910\ ft[/tex] from the base of the mountain
From the figure, length of the shortest path is [tex]l[/tex]
It is given by using Pythagoras theorem
[tex]\Rightarrow l^2=3900^2+910^2\\\Rightarrow l=\sqrt{(3900)^2+(910)^2}\\\Rightarrow l=4004.76\ ft[/tex]
hi, please solve these three questions for me, i have to shoe solving steps.
question 3
Step-by-step explanation:
i only able to show you the step of question 3..so sorry
Evaluate the expression when x=-6.
x^2-9x+4
Answer:
- 14
Step-by-step explanation:
x = - 6
x^2 - 9x + 4
= ( - 6 )^2 - 9 ( - 6 ) + 4
= 36 + 54 - 4
= 36 - 50
= - 14
Answer:
[tex]94[/tex]
Step-by-step explanation:
[tex]x^2 - 9x + 4[/tex]
[tex](−6 {)}^{2} −9 (−6) + 4[/tex]
[tex]36 − 9 (−6) + 4[/tex]
[tex]36 + 54 + 4[/tex]
[tex]90+4[/tex]
[tex]94[/tex]
Hope it is helpful....Pamela is 14 years younger than Jiri. The sum of their ages is 52. What is Jiri's age?
Answer:
33
Step-by-step explanation:
Pamela-x
Jiri-x+14
x+x+14=52
2x=52-14
2x=38
x=19-Pamela
19+14=33-Jiri
check: 19+33=52
Answer: Jiri is 33 years old, and Pam is 19.
Step-by-step explanation:
Let's put Jiri as x, and Pam as y. We know that Pam's and Jiri's age =52. Pam is 14 years younger than Jiri(x)
You can model the situation by two equations:
y=x-14
x+y=52
Substitute y into second equation
x+x-14=52
2x=66
x=33
Jiri is 33
and back to the first equation
y=33-14=19, Pamela's age.
Answer the question to get points
Answer:
4. E=4x-15(vertically opposite)
F=E(corresponding angles)
E=4x-15
5.3x+6x+O=180(angles on a straight line)
9x+0=180
9x=180-0
9x/9=180/9
x=20
What is the total surface area of the square pyramid below?
14 cm
10 cm
10 cm
O 100 cm
O 200 cm
O 280 cm?
O 380 cm?
a
Answer:
D
Step-by-step explanation:
380
Write the exponential function that passes through (-1, 27), (0, 9), (1, 3).
Step-by-step explanation:
we see, for x=-1 we get 3³
x=0 we get 3²
x=1 we get 3¹
so the function is definitely a 3 to the power of x version.
but we need to adapt the exponent a bit and correct x, so that at least for these 3 values of x the result is "running backwards".
the easiest way : 2-x as exponent.
it fits.
for x=-1 we get 2 - -1 = 3 as exponent.
for x=0 we get 2-0 = 2 as exponent.
for x=1 we get 2-1 = 1 as exponent.
so, the exponential function passing through these 3 points is
[tex]f(x) = {3}^{2 - x} [/tex]
11. Find out price elasticity of demand from the following table:
Price per unit()=8,10
Quantity Demanded (Units)=200,150
Answer:
Price elasticity of demand = 1
Step-by-step explanation:
Old quantity demanded = 200
New quantity demanded = 150
Old price = 8
New price = 10
Price elasticity of demand = percentage change in quantity demanded / percentage change in price
percentage change in quantity demanded = change in quantity demand / old demand × 100
= 50/200 × 100
= 0.25 × 100
= 25%
percentage change in price = change in price / old price × 100
= 2/8 × 100
= 0.25 × 100
= 25%
Price elasticity of demand = percentage change in quantity demanded / percentage change in price
= 25% / 25%
= 1
Price elasticity of demand = 1
