1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
levacccp [35]
3 years ago
5

A toxic radioactive substance with a density of 7 milligrams per square centimeter is detected in the ventilating ducts of a nuc

lear processing building that was used 45 years ago. If the half-life is 20 years, what was the density of the substance when it was deposited 45 years ago?
Mathematics
1 answer:
uysha [10]3 years ago
5 0
For this case we have an equation of the form:
 y = A * (b) ^ t
 Where,
 A: initial amount
 b: decrease rate
 t: time in years.
 Substituting values we have:
 7 = A * (0.5) ^ ((1/20) * t)
 For t = 45 years we have:
 7 = A * (0.5) ^ ((1/20) * 45) 
 Clearing A:
 A = 7 / ((0.5) ^ ((1/20) * 45))
 A = 33.3
 Answer:
 
the density of the substance when it was deposited 45 years ago was:
 
A = 33.3 milligrams per square centimeter
You might be interested in
Using Triangle Congruence Theorems
kodGreya [7K]

There are a total of five theorems congruent triangles. They are summarized as:

  • SAS
  • SSS
  • AAS
  • RHS and
  • ASA.

<h3>What are the definitions of the Theorems of Congruent Triangles?</h3>

SAS - Side Angle Side

According to the SAS rule, two triangles are said to be congruent if any two sides and any angle between the sides of one triangle are equal to the corresponding two sides and angle between the sides of the second triangle.

SSS - Side Side Side Rule

According to the SSS rule, two triangles are said to be congruent if all three sides of one triangle are proportional to the size three sides of the second triangle.

AAS - Angle Angle Side Rule
Angle-Angle-Side is abbreviated as AAS. The triangles are said to be congruent when two angles and a non-included side of one triangle match the comparable angles and sides of another triangle.

ASA - Angle Side Angle rule

According to the ASA rule, two triangles are said to be congruent if any two angles and the side contained between the angles of one triangle are proportional to the size two angles and side included in between angles of the second triangle.

RHS - Right Angle- Hypotenuse side Rule

According to the RHS rule, two right triangles are said to be equivalent if their hypotenuses and one of their sides are identical to those of another right-angled triangle.

Learn more about theorems of congruent triangles at:
brainly.com/question/2102943
#SPJ1

4 0
2 years ago
I need some help pls :'(
Luda [366]

Answer:

a

Step-by-step explanation:

4 0
2 years ago
Factor x2 + 29x - 30.
marysya [2.9K]
Ok the w to your question is to cross multiply <span>216=9m m=24

</span>
8 0
3 years ago
Read 2 more answers
If a circle garden has a diameter of 60 feet and there’s a sidewalk 18 feet from the center, how long is the sidewalk?
Paul [167]

Answer:

Step-by-step explanation:

Conditions

  • A diameter must be chosen such that it meete the sidewalk perpendicular to itself.
  • The diameter meets the sidewalk at the sidewalk's midpoint.
  • The diameter meets the sidewalk such that the diameter is cut into two segments 30+18 and 12
  • The sidewalk is cut in 1/2 where the diameter meets the sidewalk as the diagram shows.
  • If all these conditions are met, the relationship between the four lines is

Equation

48/12 = x^2

Solution

4 = x^2

sqrt(x^2) = sqrt(4)

x  = 2

The length of the sidewalk is 4. Why is it doubled.

Because there are 2 xs of equal length

8 0
3 years ago
Consider the function represented by the equation y-6x-9=0. Which answer shows the equation written in function notation with x
Marta_Voda [28]

Answer:

A. f(x) = 6x + 9

Step-by-step explanation:

The given equation is:

y - 6x - 9 = 0

We have to write this equation in function notation with x as the independent variable. This means that y will be replaced by f(x) and all other terms will be carried to the other side of the equation to get the desired function notation.

y - 6x - 9 = 0

y = 6x + 9

f(x) = 6x + 9

Therefore, option A gives the correct answer.

5 0
3 years ago
Read 2 more answers
Other questions:
  • Rewrite 3/7 with a denominator of 28
    12·1 answer
  • In a sale, the cost of a coat is reduced from $85 to $67.50 .
    14·2 answers
  • Which of the following correctly shows the quadratic formula?
    9·2 answers
  • What is the answer of y=4x-6
    8·2 answers
  • A circle has a circumference of 16 7 feet. What is the<br> radius of the circle, in feet?
    8·1 answer
  • or the past 50 days, daily sales of laundry detergent in a large grocery store have been recorded (to the nearest 10). Units Sol
    5·1 answer
  • The perimeter of a rectangular painting is 272 cm if the width of the painting is 61 cm, what is its length?
    5·1 answer
  • After taxes, Darius made $18,518.50 for winning the national fortnite competition. If taxes were 50% how much did Darius win
    9·1 answer
  • in a mixed school, the ratio of boys to girls was 15:11. if there were 435 boys. What is the number of girls
    12·2 answers
  • Complete the sentence.<br> 32 g≈ ___ oz
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!