An accident in a laboratory results in a room being contaminated by a radioisotope with a half-life of 8 days. If the radiation is measured to be eight times the maximum permissible level, how much time must elapse before the room is safe to enter?

Answers

Answer 1

Answer:

24 days

Step-by-step explanation:

Let the permissible time be Ro

Let the initial activity be R= 8Ro

From;

0.693/t1/2 × t= 2.303 log R/Ro

Half life of the radionuclide= t1/2 = 8 days.

Hence;

0.693/8 × t = 2.303 log 8

t= 2.1/0.087

t= 24 days


Related Questions

I also need help with this question I’m confused

Answers

Answer:

x = 4

Step-by-step explanation:

From the diagram, we can se that line l is parallel to m. This means that according to geometry, m<7 and m<9 are located on the same position on line n. Hence m<7 = m<9 (corresponding angle)

Given

m<7 = 9x+ 5

m<9 = x+37

Equaling both

9x + 5 = x+ 37

9x - x = 37-5

8x = 32

x = 32/8

x = 4

Hence the value of x is 4

PLEASE TAKE A PIC OF YOU WORK ON A PECIE OF PAPER WITH THE AWNSER ON IT!!!! Hey! I need help with this! I’m bad at math and have a 55% in it rn it would mean a lot if you could take this seriously. Only 5 questions.

Answers

Answer:

Step-by-step explanation:

Hey if you give me your email i ca email you the aswer it wot let me link a photo lol

Am I supposed to solve for x? Or.....? There’s no instruction?

This year Rachel watched 65 movies she thought that 26 of them were very good of the movies she watched what percentage did she think we’re very good

Answers

Answer:

40%

Step-by-step explanation:

26×100=2600÷65=40

40%×65=26

EASY MATH PLS HELP
For f(x)= 19-5x, what is the value of f(-3)?

Answers

Answer:

f(x)= 19-5(-3)

19+15

f(x)=34

Step-by-step explanation:

Four ninths plus one ninth

Answers

Answer:

5/9

Step-by-step explanation:

Answer:

5/9

Step-by-step explanation:

4/9 + 1/9

To add fractions, you need a common denominator. You already have a common denominator of 9, so just add the numerators.

4/9 + 1/9 = 5/9

Since there is no common factor of 5 and 9 other than 1, the fraction is already reduced.

Answer: 5/9

Find the measure of angle A.

Answers

Answer:

I had this question and i got it right it is the measure is four

Step-by-step explanation:

Sara and Harry are putting together a puzzle. Sara put together 7/12 of the puzzle pieces. Harry put together 7/24 of the puzzle pieces. What fraction of the total number of puzzle pieces has NOT been used? Enter your answer as a fraction, in simplest form, in the box provided.

Answers

Answer:

1/8

Step-by-step explanation:

7/12= 14/24                                    14/24 + 7/24= 21/24                    

21/24= 7/8           1-7/8= 1/8

The fraction of the total number of puzzle pieces has not been used is 1/8.

What is an expression?

The mathematical expression combines numerical variables and operations denoted by addition, subtraction, multiplication, and division signs.

Mathematical symbols can be used to represent numbers (constants), variables, operations, functions, brackets, punctuation, and grouping. They can also denote the logical syntax's operation order and other properties.

Given that Sara and Harry are putting together a puzzle. Sara put together 7/12 of the puzzle pieces. Harry put together 7/24 of the puzzle pieces.

The fraction of the total number of puzzle pieces has not been used is calculated as,

7/12= 14/24      

21/24= 7/8        

1-7/8= 1/8

To know more about an expression follow

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The length of a rectangular piece of cardboard is 2 cm greater than its width. If the length and the width were each decreased by 1 cm, the area of the cardboard would be decreased by 27 cm². What are the dimensions of the original piece of cardboard?

Write and solve an equation to represent the problem.

Answers

9514 1404 393

Answer:

  13 cm wide;  15 cm long

Step-by-step explanation:

Let w represent the original width. Then the original length is (w+2) and the original area is w(w+2). After the decrease, the width is (w-1) and the length is (w+1). The decreased area is (w-1)(w+1). The difference between these areas is 27, so we have ...

  w(w+2) -(w-1)(w+1) = 27

 w^2 +2w -(w^2 -1) = 27

 2w +1 = 27

  w = (27-1)/2 = 13

The original piece of cardboard was 13 cm wide and 15 cm long.

From A to Z BU
9 Love From A to Z
9 Love From A to Z
20
The
equation d = n²-12n + 43
models the number of defective
items d
produced in a manufacturing process where there
workers in a restricted
are n
area
a) solve for
When
do 30
I
b) solve for n
when
d=20

Answers

Answer:

a) we get value of n: n=10.7 or n=1.2 when d=30

b) we get value of n: n=9.6 or n=2.3 when d=20

Step-by-step explanation:

a) solve for  n When  do= 30

Put d= 30 in the given equation:

[tex]d = n^2-12n + 43[/tex]

[tex]30=n^2-12n+43\\n^2-12n+43-30=0\\n^2-12n+13=0\\[/tex]

Now, we will find value of n by using quadratic formula: [tex]x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}[/tex]

We have a=1, b=-12 and c=13

[tex]n=\frac{-b\pm\sqrt{b^2-4ac}}{2a}\\n=\frac{-(-12)\pm\sqrt{(-12)^2-4(1)(13)}}{2(1)}\\n=\frac{12\pm\sqrt{144-52}}{2}\\n=\frac{12\pm\sqrt{92}}{2}\\n=\frac{12\pm9.59}{2}\\n=\frac{12+9.59}{2} , n=\frac{12-9.59}{2}\\n=10.7 , n=1.2\\[/tex]

So, we get value of n: n=10.7 or n=1.2

b) solve for n  when  d=20

[tex]d=n^2-12n+43\\20=n^2-12n+43\\n^2-12n+43-20=0\\n^2-12n+23=0\\[/tex]

Now, we will find value of n by using quadratic formula: [tex]x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}[/tex]

We have a=1, b=-12 and c=23

[tex]n=\frac{-b\pm\sqrt{b^2-4ac}}{2a}\\n=\frac{-(-12)\pm\sqrt{(-12)^2-4(1)(23)}}{2(1)}\\n=\frac{12\pm\sqrt{144-92}}{2}\\n=\frac{12\pm\sqrt{52}}{2}\\n=\frac{12\pm7.21}{2}\\n=\frac{12+7.21}{2} , n=\frac{12-7.21}{2}\\n=9.6 , n=2.3\\[/tex]

So, we get value of n: n=9.6 or n=2.3

Rectangle LMNO is reflected over the x-axis to create rectangle L'M'N'O'. If a line segment is drawn from point M to point M', which statement would best describe the relationship between segment M M prime and the x-axis? They are diameters of concentric circles. They share the same midpoints. They are perpendicular to each other. They share the same endpoints.

Answers

Answer:I am pretty sure the answer is

C. "They are perpendicular to each other."

Step-by-step explanation:

For a shape to be reflected, it must be reflected across a line.

The true statement about the relationship between segments M, M' and the x-axis is that (c) they are perpendicular to each other

Given that:

Shape: rectangle LMNOReflection line: x-axis

When the shape is reflected across the x-axis, we have the following perpendicular and congruent lines

L x-axis and L' x-axis M x-axis and M' x-axis N x-axis and N' x-axis O x-axis and O' x-axis

Hence, the relationship between segments M, M' and the x-axis is that (c) they are perpendicular to each other

Read more about reflection at:

https://brainly.com/question/18549175

Complete the congruence statement by naming the corresponding angle or side.
50 points

Answers

Step-by-step explanation:

Triangles RQP and RBC are congruent.

Letters R and P are the 1st and 3rd letters in RQP.

Letters R and C are the 1st and 3rd letters in RBC.

Hence line RP = line RC = line CR (D).

D) CR

ΔRQP ≅ ΔRBC

They are congruent so if you highlight the line PR and find the similar one,

ΔRQP ≅ ΔRBC

The line would be line CR.

Twice a number is 42 less than five times a number. What is the number?

Answers

Answer:

21

Step-by-step explanation:

I am 90% sure but tell me if i'm wrong

Plzzzz help!

What is the equation of the line that passes through the point (2,-6) and has a
slope of -12

Answers

Y=-12x+18
Hope this helps :)

Joselyn saw an alligator that was 5 feet long. How many inches is 5 feet.

Answers

Answer:

The alligator is 60 Inches long.

Step-by-step explanation:

5 feet is 60 inches.

hope it helps!

Answer:

60 inches

Step-by-step explanation:

There are 12 inches in 1 foot, therefore the ratio of inches to feet is 12:1.

If the alligator is 5 feet than the amount of inches increase.

In order to find how long the alligator is in inches, multiply 5 by 12

5 x 12 = 60

The following list gives the number of siblings for each of 11 students. 0, 8, 9, 6, 5, 7, 2, 4, 3, 1, 11 Find the modes of this data set. If there is more than one mode, write them separated by commas. If there is no mode, click on "No mode."​

Answers

Answer:

[tex]0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11[/tex]

Step-by-step explanation:

Given

[tex]0, 8, 9, 6, 5, 7, 2, 4, 3, 1, 11[/tex]

Required

Determine the mode

Though, not necessary; it is a good practice to order the given data either in ascending or descending order.

In ascending order, the ordered data are:

[tex]0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11[/tex]

Mode implies that: the data that has the highest number of occurrence.

In the given data, each data has a frequency of 1.

Hence, the mode is:

[tex]0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11[/tex]

be The distance an object travels is determined by how fast it goes and for how long it moves. If an object's speed remains constant, the formula is d= r., where d is the distance, ris the speed, and t is the time. a. If you drive at 50 miles per hour for 5 hours, how far will you have traveled? 200 miles b. 10 miles 250 miles d. 300 miles C. Please select the best answer ​

Answers

Answer:

10 miles is answer because u should divide d=r

What is the volume of the following rectangular prism?
units
NI
1
16- units
4.

Answers

Answer:

60

Step-by-step explanation:

The volume of the rectangular prism is V = 64 units³

What is the volume of a prism?

A three-dimensional solid object called a prism has two identical ends. It consists of equal cross-sections, flat faces, and identical bases. Without bases, the prism's faces are parallelograms or rectangles.

The volume of a prism is the product of its base area and height

Volume of Prism = B x h

where B = base area of prism

h = height of prism

Given data ,

Let the volume of the rectangular prism be represented as V

Now , the height of the prism is H = 4 units

The length and width of the prism is 1 and 16 units respectively

So , the base area of the prism B = 16 units²

Now , Volume of Prism = B x h

On simplifying , we get

The volume of rectangular prism V = 16 x 4

The volume of rectangular prism V = 64 units³

Hence , the volume of the rectangular prism is 64 units³

To learn more about volume of rectangular prism click :

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Anthony is 154 cm tall, his brother Gerry is 5/7 as tall as him. How tall is Gerry?

:D can someone please help me with these problems please

Answers

The correct answer is 110 cm

Explanation:

Fractions always include two values (one at the top and the other at the bottom) and they represent the proportion of something, for example, 1/2 of an apple means there is only half apple. Now, to calculate how much is 5/7 of 154 centimeters, simply divide the total number into the denominator (bottom number) and then multiply the result by the numerator (top number). This process is shown in detail below:

[tex]\frac{5}{7}[/tex]  -  5 is the numerator and 7 is the denominator

5/7 of 154 cm

154 cm / 7 = 22

22 x 5 = 110 cm

Plot -7 in the complex plane.

Answers

Answer:

the phone with me and I will be in the future of our games in call of duty Black ops game clip is not available for remote playback of the phone with me know if I can be used for

Step-by-step explanation:

explain the IF

poem in 5 linesexplain the IF

poem in 5 lines

explain the IF

poem in 5 linesexplain the IF

poem in 5 linesexplain the IF

poem in 5 linesexplain the IF

poem in 5 linesexplain the IF

poem in 5 linesexplain the IF

poem in 5 linesexplain the IF

poem in 5 linesexplain the IF

poem in 5 linesexplain the IF

poem in 5 linesexplain the IF

poem in 5 linesexplain the IF

poem in 5 linesexplain the IF

poem in 5 linesexplain the IF

poem in 5 linesexplain the IF

poem in 5 linesexplain the IF

poem in 5 lines

The Student Council sold the following items at the home football game. A B с D E F G H

Item Price Income Cost Per Expenses Profit Number Sold Item 2 lollipops 85 $21.25 $0.12 $10.20 $11.05 $8.16 3 Gummies 48 $16.80 $0.18 $0.25 $0.35 $0.45 $0.55 4 Bubble Gum 79 $35.55 $8.64 $17.38 $11.96 $0.22 $0.26 $18.17 5 Combos 46 $25.30 $13.34 $50.72 6 TOTAL: $50.72

i stands for income and e stands for expenses, what is the formula for p, profits?

A: p = i/e
B: p = e/i
C: p = e-i
D: p = i-e​

Answers

Answer:

[tex]p = i - e[/tex]

Step-by-step explanation:

Given

[tex]i = income[/tex]

[tex]e = expenses[/tex]

Required

Determine the profit (p)

Profit (p) is the difference between income (i) and expenses (e)

.

Mathematically:

[tex]Profit = Income - Expenses[/tex]

i.e.

[tex]p = i -e[/tex]

Option D is correct.

Answer:

d

Step-by-step explanation:

Write the equation 8x - 5y = 20 in
slope intercept form.

Answers

Answer:

The equation in slope-intercept form is y = 8/5x-4.

I hope this helps! Have a nice day!!

Best answer gets Brainliest!!!!

Answers

Answer:

no

Step-by-step explanation:

if it was the amount of time would be going up at a constant rate but its not

and your graph is wrong

hope this helps <3

sorry if this is wrong this is a weird question :/

What is the relationship between the length of one leg and the length of the hypotenuse of an isosceles right triangles?
A) Leg = Hypotenuse ∙ √2
B) Hypotenuse = Leg ∙ √2
C) Leg ∙ Hypotenuse = √2

Answers

Answer:

B) Hypotenuse = Leg ∙ √2

Step-by-step explanation:

This is a well-known ratio in the 45-45-90 right triangle, but we can derive it.

An isosceles right triangle has two congruent legs forming the right angle and the hypotenuse opposite the right angle. The Pythagorean theorem works since it is a right angle.

Normally, the legs are a and b, and the hypotenuse is c, and we have

a^2 + b^2 = c^2

Here the legs are congruent, so we have a = b.

Substituting a for b, we have

a^2 + a^2 = c^2

2a^2 = c^2

c^2 = 2a^2

c = a√2

Answer: B) Hypotenuse = Leg ∙ √2

Answer:

progably B) Hypotenuse = Leg ∙ √2

Step-by-step explanation:

find the number of permutations of the letters in twelve

Answers

Answer:

360

Step-by-step explanation:

Six letters in twelve with a repeated e would be 6! ÷ 2

pleaseee helppp meeee

helppp meee​

Answers

Answer:   Slope = -1.000/2.000 = -0.500

 x-intercept = 0/1 = 0.00000

 y-intercept = 0/2 = 0.00000

Step-by-step explanation:

I need help with this !

Answers

The third one because they equal 90

Answer:

the one closer to the right with the 56 and 34

try adding the angle's degree.

Step-by-step explanation:

Helpppppppppppppppppppppppppppppp

Answers

Answer:

Step-by-step explanation:

c and e is not polynomials

A parallelogram is a:
rectangle
square
quadrilateral
rhombus

Answers

Answer:

quadrilateral

Step-by-step explanation:

A quadrilateral that has two pairs of parallel sides.

The radius of a cylindrical tank is 3' and the height is 8'what is the volume

Answers

Answer:

226 cubed foot (rounded to 3 s.f.)

Step-by-step explanation:

Volume of cyclinder: [tex]\pi[/tex] × r² × h

Volume of cylindrical tank = [tex]\pi[/tex] × 3² × 8

                                           = 72[tex]\pi[/tex]

                                           = 226 cubed foot (rounded to 3 s.f.)

the following formula gives the area of a circle, A, dependent on its radius, r.

A = πr²

solve the equation for the variable r.

Answers

Answer:

sqrt(A/pi), -sqrt(A/pi)

Step-by-step explanation:

A=pi*r^2

r^2=A/pi

r=sqrt(A/pi), -sqrt(A/pi)

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