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
bogdanovich [222]
3 years ago
6

A toxic radioactive substance with a density of 2 milligrams per square centimeter is detected in the ventilating ducts of a nuc

lear processing building that was used 55 years ago. If the​ half- life of the substance is 20 ​years, what was the density of the substance when it was deposited 55 years​ ago?
Mathematics
1 answer:
Zolol [24]3 years ago
3 0

Answer:

60.5 milligrams per square centimeter First, determine how many half lives have expired by dividing the time by the half-life. So: 55/20 = 2.75 That means that only 2^(-2.75) = 0.148650889 = 14.8650889% of the original substance remains. So just divide the amount remaining by 0.148650889 to get the original amount. 9 / 0.148650889 = 60.5445419 So originally, there was 60.5 milligrams per square centimeter 55 years ago.

You might be interested in
What is the domain of g
irakobra [83]

Answer:

We conclude that the set of numbers x satisfying -7 ≤ x ≤ 4 is an interval that contains -7, 4, and all numbers in between.

Thus, the domain of g is: -7 ≤ x ≤ 4

Step-by-step explanation:

We know that the domain of a function is the set of inputs or argument values for which the function is defined.

From the given graph, it is cleared that the function g starts from the x-value x = -7 and ends at x = 4.

It means the function is defined for the set of input values from x = -7 to x = 5 for which the function is defined.

Therefore, we conclude that the set of numbers x satisfying -7 ≤ x ≤ 4 is an interval that contains -7, 4, and all numbers in between.

Thus, the domain of g is: -7 ≤ x ≤ 4

4 0
3 years ago
Given the diagram below what is tan 60?
Contact [7]

Answer:

A) √3

Step-by-step explanation:

The tangent of an angle can be found by dividing the leg opposite the angle over the leg adjacent to it.

So, we have to find them.

The 30-60-90 rule says that in a right triangle with the angles 30°, 60° and 90°, the sides opposite those angles will have the ratio of 1:√3:2.

That means the side adjacent to 60° is 2 units long and the one opposite is 2√3 units long.

Dividing those two gives us (2√3)/2, which can be simplified to √3.

3 0
3 years ago
Read 2 more answers
Heba ate 1/12 of a box of cereal. Now the box is 3/4 full.
Alex Ar [27]
3/4 = 3/4*1

3/4 = 3/4 * 3/3 = 9/12

Box is 9/12 full after heba ate 1/12 of a box of cereal

Initial fraction will be 9/12+1/12

=10/12= 5/6
5 0
3 years ago
Eight sided dice can be described as two square based pyramids stuck together at
kobusy [5.1K]
It costs $3.63 more for the gold die than the gold plated die.

The volume of each half of the die is given by the formula

V=1/3s³.

This means the total volume is V = 2(1/3s³) = 2(1/3(2³)) = 16/3 = 5.33 mm³.

For the solid gold die, we know that it weighs 0.02g per mm³:

5.33(0.02) = 0.1066g

Gold costs $40.38 per gram:
40.38(0.1066) = $4.30

For the plastic die, plastic weighs 0.01 g per mm³:
0.01(5.33) = 0.0533g

Plastic costs $10 per gram:
0.0533(10) = 0.533 ≈ $0.54.

We also need to find the surface area, as it will be painted.  Each face is an equilateral triangle; the area of a triangle is given by the formula

A = 1/2bh

We need to use the Pythagorean theorem to find the height.  The height will be one leg and 1/2 of the base will be the other; the slanted side will be the hypotenuse:

h² + (1/2(2))² = 2²
h² + 1² = 2²
h² + 1 = 4
h² = 3
h = √3

The area of the triangle would then be A = 1/2bh = 1/2(2)(√3) = √3.  There are 8 such faces on the die, so the total surface area would be 8√3 = 13.86mm².

Paint costs $0.01 per mm²:
13.86(0.01) = 0.1386 ≈ $0.14

Together the cost for the plastic is 0.14+0.53 = $0.67.

The difference between it and the cost for the gold die is 4.30 - 0.67 = $3.63.
5 0
3 years ago
8) Shawna had $20 to spend on six pencils. After buying them she had
Brums [2.3K]

It cost 2 dollers each.

3 0
3 years ago
Other questions:
  • alissa's monthly budget is $1500. she spends 30% on rent. How much does she spent on the rent? A)$250 B)300 C)450 D)500
    9·2 answers
  • The legs of a right triangle are 12 centimetres and 16 centimeters. What is the length of the hypotenuse?
    10·2 answers
  • I need help so someone plz give me the steps and answer and graph it so i can understand how to solve these types of problems ag
    11·2 answers
  • Divide 33 Photos into two groups so the ratio is 4 to 7
    15·1 answer
  • The number of customers waiting for gift-wrap service at a department store is an rv X with possible values 0, 1, 2, 3, 4 and co
    5·1 answer
  • I NEED HELP QUICKLY... The Student Council is selling raffle tickets to raise money for the Winter Dance. They have a total of 2
    15·2 answers
  • Need help take your time and thx
    9·1 answer
  • John sold a car for 60,000 dollars and made a profit of 20%.what is the cost price of the car​
    8·1 answer
  • Solve the inequality. -x ≤ 5​
    8·2 answers
  • Calculate the interest amount for a loan of $800 at 4.25% simple interest for 6 years.
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!