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
Evaluate f(2)=-3x+1
bearhunter [10]
The correct answer is -5
4 0
2 years ago
Read 2 more answers
What is the equation for the opposite of the opposite of 25?
otez555 [7]
O oposto de 2 é 1/2
o oposto de 8 é 1/8
chamando o oposto de 25 de x
x = 1/25
4 0
3 years ago
Read 2 more answers
Guyssss helppppp please
patriot [66]

0.45

90/2=45% chance they will go               110/2=55% chance they won't go

7 0
2 years ago
Find all the zeros of f(x) help please
Licemer1 [7]

Since f(6)=0, by the remainder theorem this means that <em>x</em> - 6 divides <em>f(x)</em> exactly. This means there are constants <em>a</em>, <em>b</em>, and <em>c</em> such that

\dfrac{f(x)}{x-6} = ax^2 + bx + c

Multiplying both sides by <em>x</em> - 6 gives

f(x) = (x-6)(ax^2+bx+c) \\\\ 2x^3-19x^2+45x-18 = ax^3 + (b-6a)x^2 + (c-6b)x - 6c

Then <em>a</em>, <em>b</em>, <em>c</em> satisfy

\begin{cases}a=2 \\ b-6a=-19 \\ c-6b=45 \\ -6c=-18\end{cases}

and solving this system gives <em>a</em> = 2, <em>b</em> = -7, and <em>c</em> = 3.

So, we have

2x^3-19x^2+45x-18 = (x - 6) (2x^2 - 7x + 3)

The quadratic term can be factored as

2x^2 - 7x + 3 = (2x - 1)(x - 3)

which leaves us with

f(x) = (x-6)(2x-1)(x-3)

so that the zeros of <em>f(x)</em> are 6, 1/2, and 3.

4 0
2 years ago
A drama club earns $1040 from a production. It sells a total of 64 adult tickets and 132 student tickets. An adult ticket costs
Mashutka [201]
The system of equations would be:

64x+132y = 1040
x = 2y

We multiply the number of adult tickets, 64, by the cost of the adult tickets, x.   We multiply the number of student tickets, 132, by the cost of the student tickets, y.  Together these add up to $1040.

We know that the cost of an adult ticket is twice as much as a student ticket, so x = 2y.
4 0
3 years ago
Other questions:
  • What are the counting numbers in base 6
    6·1 answer
  • There are 1500 bees in a colony. Each month, the number of bees decreases by 12%. There are 800 flowering plants in a garden. Ea
    13·1 answer
  • Estimate the difference.<br> 6.11 - 1.2<br> 5
    13·1 answer
  • Item 36 Solve for x. x ÷ 9 = 8 x = 72 x = 17 x = 1.11 x = 1
    9·1 answer
  • Suppose a shirt is on sale for 10% off it’s original price $23.50.
    9·1 answer
  • How can you describe the solution 16x^2-8x+1=0
    6·1 answer
  • The price of a theater tickets 56.89.There are 22 seats in each row of the theater .How much would it cost to buy tickets for 2
    10·2 answers
  • Doris is playing a game. She rolls three six-sided number cubes to tell her how many squares to move. If two number cubes show 4
    13·1 answer
  • The figure shows circle C with tangent lines QR and SR.
    8·1 answer
  • Saba spent 2/3 of the pay from her Saturday job, on clothes.
    5·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!