Answer:
k = 0.086
Step-by-step explanation:
We have the equation
y=ne^(-kt)
where y is the amount of radioactive material after t hours, n is the initial amount of radioactive material, and k is some constant.
We know the following data:
t: 8 hoursy = n/2 (half of a radioactive element remains)Replacing into the equation and solving for k:
[tex]y=ne^{-kt}[/tex]
[tex]\frac{n}{2}=ne^{-k8}[/tex]
[tex]0.5=e^{-k8}[/tex]
[tex]ln(0.5)=ln(e^{-k8})[/tex]
[tex]ln(0.5)=-k8ln(e)[/tex]
[tex]\frac{ln(0.5)}{-8}=k[/tex]
[tex]\frac{ln(0.5)}{-8}=k[/tex]
[tex]k = 0.086[/tex]
CAN SOMEONE PLEASE HELP The Ecology Club was planning to take a field trip either to the seacoast or the mountains. The club president surveyed all of the members to determine the preferred trip. The results are displayed in the table below. Which statement is true about the results of the survey? *
20% of eighth-grade students preferred the seacoast
32% of seventh-grade students preferred the mountains
40% of students preferred the mountains
48% of students preferred the seacoast
Answer:
The true statement about the results of the survey is:
48% of students preferred the seacoast.Step-by-step explanation:
To identify if the D option is right, you only must use a simple rule of three, where you use the total of the members surveyed in the club (150), and the number of members that preferred the seacoast (72), by the last the operation must confirm that this value (72) is equal to the 48% (how says in the D option). First, you must establish the rule of three:
150 = 100 (100% of surveyed really, but is easier to understand in this form) 72 = XAnd operate:
X= (72 * 100) / 150 X = 48 (this means the 48%)How you can see, the value obtained in the simple rule of three is exactly the percentage of the D option, for this reason, this is the true statement.
A circular lawn has a row of bricks around the edge. The radius of the lawn is about 20 feet.
Which is the best estimate for the area of the grass in the lawn? Use 3.14 for π. Select One.
125 feet
125 square feet
1250 feet
1256 square feet
Answer:1256
Step-by-step explanation:
You need to find the area which is Area=3.14xradiusxradius
So in short hand A=3.14x20x20 which is 1256 feet
The diameter of a cylinder is 10 feet. The height of the cylinder is 15 feet. What is the approximate volume of the cylinder rounded to the nearest cubic foot? Use 3.14 for π.
Answer:
1,178 cubic feet
Step-by-step explanation:
volume of cylinder is given by following formula
volume = [tex]\pi r^2l[/tex]
where r is the radius for cylinder and l is the height of cylinder.
____________________
given
diameter of cylinder = 10 feet
radius is half diameter
thus, radius = diameter/2 = 10/2 = 5 feet
height of the cylinder = 15 feet.
[tex]volume = \pi r^2l\\=> volume = 3.14* 5^2*15\\=> volume = 3.14* 25*15 = 1,177.5[/tex]
Thus, volume of cylinder is 1,177.5 cubic feet
volume of cylinder,rounded to the nearest cubic foot, is 1,178 cubic feet.
Josh has $9.00. Bagels cost $0.70 each and a small container of cream cheese cost $2.50. What is the greatest number of bagels Josh can buy if he buys one small container of cream cheese?
Answer:
Josh's 9.00
Bagel cost 0.70
Ice cream 2.50
9.00–2.50=6.50
6.50
[tex]6.50 \div 0.70 7[/tex]
=10
BC⎯⎯⎯⎯⎯ is parallel to DE⎯⎯⎯⎯⎯. What is AC? Enter your answer in the box. 34 units A triangle with vertices labeled as A, D, and E. Side D E is the base and the top vertex is A. Sides A D and A E contain midpoints B and C, respectively. A line segment is drawn from point B to C. Side A B is labeled as 8. Side B D is labeled as 10. Side C E is labeled as 15.
Answer:
AC = 12
Step-by-step explanation:
If BC is parallel to DE, then angles D and B are congruent and angles C and E are congruent as well. This means that triangles ABC and ADE are similar by the AAA (or AA) similarity theorem.
We know that similar triangles are in proportion. This means that [tex]\frac{AC}{AE} = \frac{AB}{AD}[/tex]
Now, we can plug the values given into that equation:
[tex]\frac{x}{x+15} = \frac{8}{18}[/tex]
Now, cross multiply:
18x = 8(x + 15)
Now, we can simplify this equation and solve for x, or AC.
18x = 8x + 120
Subtract 8x from both sides:
10x = 120
Divide both sides by 10:
x = 12
Hope this helps!
Answer:
AC: 12
Step-by-step explanation:
Please help ASAP Very easy !!!!
Answer:
Brainleist is to be given to me!
Step-by-step explanation:
-2/3
its between -1 and 0 but is closer to -1
the only choises are -1/3 and -2/3 but its closer to -1 so it must be -2/3
Find the measurement of the inscribed angle CDB indicated below
Answer:
∠ CDB = 45°
Step-by-step explanation:
The measure of an inscribed angle is half the measure of its intercepted arc.
∠ CDB = 0.5 × BC = 0.5 × 90° = 45°
A line passes through the point (-3,1) and has a slope of -2
Answer:
Step-by-step explanation:
y - 1 = -2(x + 3)
y - 1 = -2x - 6
y - 1 + 1 = -2x - 6 + 1
y = -2x - 5
8. ABCD is a quadrilateral. Work out the size of y.
B
2y
A
68°
y +48°
D
C
Answer:
y+48degrees
Step-by-step explanation:
Please Answer Quick!!! Will Give Brainliest!!!
1.) Rita used a compass to draw a circle with a radius of 3 cm. What was the circumference of the circle? (Use 3.14 for π.)
2.) If 20% of the 50 pennies in the roll were minted before the year 2000, then how many of the pennies were minted before 2000?
Answer:
1. 18.84cm
2. 10 Pennies
Step-by-step explanation:
Question 1:
Circumference Formula = 2 x π x radius
We will substitute π for 3.14 so the circumference = 2 x 3.14 x radius
The radius is 3 so the circumference = 2 x 3.14 x 3
2 x 3.14 x 3 = 18.84cm
Question 2:
20% as a decimal is 0.2
To find the answer just find 20% of 50
50 x 0.2 = 10
Therefore 10 pennies were minted before 2000
It takes 93 pounds of seed to completely plant a 10-acre field. How many acres can be planted per pound of seed? Round to nearest hundredth.
Answer:
9.3 acres per pound
Step-by-step explanation:
93/10
Answer the questions for 9 points and brainliest
What is the median of the data
Answer:
40
Step-by-step explanation:
The median is the line in the middle of the box
40 is the median
Use the given diagram to answer the question.
Which line is the intersection of wo of the planes
shown
Which line intersects one of the planets
Tatou
Which line has points on three of the planes shown?
Answer:
Step-by-step explanation:
1)
Lines X and W intersect 2 planes, while line Y intersects 3 and linen Z and V intersect one plane,
So, answer is lines X and W (don't know about Y, since it intersects more than two planes)
2) Lines Z and V intersect only one of the planes (the other lines intersect more than one, so don't know about them)
3) Line Y has points in all three planes (the rest have in either 2 or one planes)
The line which is the intersection of wo of the planes shown is.
1) Lines X and W intersect 2 planes, while line Y intersects 3, and lines Z and V intersect one plane,
So, the answer is lines X and W (don't know about Y, since it intersects more than two planes)
The line which intersects one of the planets Tatou is.
2) Lines Z and V intersect only one of the planes (the other lines intersect more than once, so don't know about them)
The line which has points on three of the planes shown is.
3) Line Y has points in all three planes (the rest have in either 2 or one plane)
What are the basics of geometry?Basic geometric concepts are based on three basic concepts. They are a point, a line, and a plane. We cannot specify the terms. However, it does refer to a position mark and has a precise location.
Learn more about Geometry at https://brainly.com/question/20303542
#SPJ2
If x is 5, then 6x = _____. 30 x 5 x 30
Answer:
6x = 30
Step-by-step explanation:
6x
Let x = 5
6*5 = 30
6x = 30
________________________________
Hey!!!
Solution,
X=5
Now,
6x
=6*5
=30
So the right answer is 30.
please see the attached picture for full solution
hope it helps
Good luck on your assignment
______________________________
Ram baked 946 cupcakes she sold them in a box of 22 for $16.50 a box how many boxes would she need to make at least $300?
AB is a segment with one endpoint A(-7,9) and midpoint M(8,1). Can
you find the coordinates of the other endpoint B?
Enter the x-coordinate of the other endpoint here
Enter the x-coordinate of the other endpoint here
Answer:
x-coordinate of the other endpoint: 23
y-coordinate of the other endpoint: -7
Step-by-step explanation:
To find the x-coordinate of the other endpoint, we need to find the run between the known endpoint and the midpoint
run: xM - xA = 8 - (-7) = 15
where xM and xA are the x-coordinates of M and A respectively.
The run between the other endpoint and the midpoint must be the same as before:
x - 8 = 15
x = 15 + 8
x = 23
To find the y-coordinate of the other endpoint, we need to find the rise between the known endpoint and the midpoint
rise: yM - yA1 = - 9 = -8
where yM and yA are the y-coordinates of M and A respectively.
The rise between the other endpoint and the midpoint must be the same as before:
y - 1 = -8
y = -8 +1
y = -7
Need Help ASAP will give brainliest!!!!
Answer:
Puppy' present weight = 2250 grams
Puppy last weight = 600 grams
Difference = 2250-600 = 1650
%age increase = (1650/600) x 100
= 275%
Evaluate \sqrt{-75s}
−75s
square root of, minus, 75, s, end square root where s = -3s=−3s, equals, minus, 3.
Answer:
Step-by-step explanation:
the answer is 15!
The square root of the number -√75 will be -3√5.
What is an expression?Expression in maths is defined as the collection of the numbers variables and functions by using signs like addition, subtraction, multiplication, and division.
Numbers (constants), variables, operations, functions, brackets, punctuation, and grouping can all be represented by mathematical symbols, which can also be used to indicate the logical syntax's order of operations and other features.
The square root of the number will be calculated as below:-
-√75 = - √( 3 x 3 x 5 )
= -3√5
Therefore, the square root of the number -√75 will be -3√5.
To know more about expression follow
https://brainly.com/question/723406
#SPJ2
The perpendicular line which of the following equations represents the line that passes through the point 1,-1
Answer:
The answer is the letter A
The distance between city A and city B is 22 miles. The distance between city B and city C is 54 miles. The distance betweeb city A and city C is 51 miles. What type of trianglr is created by the three cities?
Answer:
the triangle is an obtuse
Step-by-step explanation:
draw it out
Answer: Acute Triangle
Step-by-step explanation:
54 is the hypotenuse because it is the longest side.
Square all of the sides.
So
54^2=2916
51^2=2601
22^2=484
Now you have 2916=2601+484
Add the two on the right and they will be greater than 2916.
Because of that, you will have an acute triangle because 22^2+51^2>54^2
Can someone please help me ASAP
Answer:
A) 144 FT B) 300
Step-by-step explanation:
{ Area= L x W
Area= 12 x 12
Area= 144 }
{ 6x2=12
12x25= $300
If the circumference of a circle is below 72 what is the length of AB
Answer: 12
Step-by-step explanation:
The circle is 360 degrees in total
360/6 = 60
72/6 = 12
a park has a 3 meter (m) tall tether ball pole and a 6.8 m tall flagpole. the lengths of their shadows are proportional to their heights. which of the following could be the lengths for the shadows. choose two answers
Answer:
Step-by-step explanation:
6.8/3 is the scale factor
1.35*(6.8/3)=3.06
1.8*(6.8/3)=4.08
3.75*(6.8/3)=8.5
8.5-8.35=0.15
3.4-3.06=0.34
since C is closer to the right proportion, if there is no option D, it should be the 2 answer you choose
Option B is definetly right, but what about another option, is there an option D?
The ratios 3:9, 4:12, 5:15, and 6:18 are a pattern of equivalent ratios in the table below. A multiplication table. In the row labeled 1, the numbers 3, 4, 5, and 6 are highlighted. In the row labeled 3, the numbers 9, 12, 15, and 18 are highlighted. Which is another ratio in this pattern?
Answer:
7 and 21
Step-by-step explanation:
the ratios are following a 1:3 pattern. basically, whichever number is in the first row, the second row will have it times 3. So, if you chose the number 7, 7x3=21, so 7 & 21 are other ratios in the pattern
Round 100.9052 to the nearest 10th
Answer:
100.9
Step-by-step explanation:
The 10th place is the one one right after the decimal, in this case 9. Since there's a 0 next to the nine you don't have to change anything. Thus you get 100.9
Find the value of y.
Answer:
Step-by-step explanation:
DB=√(y²-25)
again DB=√(x²-36)
so √(y²-25)=√(x²-36)
squaring
y²-25=x²-36
x²=y²-25+36
or x²=y²+11
also x²+y²=(6+5)²
x²+y²=121
y²+11+y²=121
2y²=121-11
2y²=110
y²=110/2=55
y=√55
Two sides of a parallelogram measure 60 centimeters and 40 centimeters. If one angle of the parallelogram measures 1320, find the
length of each diagonal.
a.about 86.4 cm and 54.2 cm
c.about 91.7 cm and 54.2 cm
b. about 91.7 cm and 44.6 cm
d. about 86.4 cm and 44.6 cm
Answer:
b. about 91.7 cm and 44.6 cm
Step-by-step explanation:
The lengths of the diagonals can be found using the Law of Cosines.
Consider the triangle(s) formed by a diagonal. The two given sides will form the other two sides of the triangle, and the corner angles of the parallelogram will be the measure of the angle between those sides (opposite the diagonal).
For diagonal "d" and sides "a" and "b" and corner angle D, we have ...
d² = a² +b² -2ab·cos(D)
The measure of angle D will either be the given 132°, or the supplement of that, 48°. We can use the fact that the cosines of an angle and its supplement are opposites. This means the diagonal measures will be ...
d² = 60² +40² -2·60·40·cos(D) ≈ 5200 ±4800(0.66913)
d² ≈ {1988.2, 8411.8}
d ≈ {44.6, 91.7} . . . . centimeters
The diagonals are about 91.7 cm and 44.6 cm.
(8x - 6) - (7x - 9)
I hope you're open to me asking more questions in the reply <3
Answer:
x + 3
Step-by-step explanation:
Given
(8x - 6) - (7x - 9)
Distribute the first parenthesis by 1 and the second by - 1
= 8x - 6 - 7x + 9 ← collect like terms
= x + 3
The system of equation y=3/4 and y=-x+3 According to the graph, what is the solution to this system of equations?
(4, -1)
(-1.4)
(4.1)
(1.4)
Answer:
a
Step-by-step explanation:
Based on the following calculator output, determine the mean of the dataset,
rounding to the nearest 100th if necessary.
1-Var-Stats
ī = 106.142857143
Ex = 743
2.c2 = 79453
Sx = 9.90670768433
or = 9.17182909673
n = 7
min X = 98
Q = 98
Med = 100
Q3 = 116
maxX = 121
Answer:
106 1/7
Step-by-step explanation:
The line ...
ī = 106.142857143
tells you the mean of the dataset is 106 1/7.
