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
Anton [14]
3 years ago
7

A certain substance has a half-life of 4 minutes. A fresh sample of the substance weighing 90 mg was obtained. After how many mi

nutes will there be 23 mg of the substance remaining?
Mathematics
1 answer:
sveticcg [70]3 years ago
7 0
  • We are to find the time (number of minutes) is would take for 23 mg of the substance to be remaining.

  • The formula for time is written as:

t =  [t1/2 x In(Nt/No)]  / In 2

where:

t1/2 = Half life = 4 minutes

No = Initial quantity of the sample = 90 mg

Nt = Amount of the sample left = 23 mg

t =  time elapsed = ?

Hence,

t = [4 x In (23/90)] / -In 2

t = 7.8731645610906 minutes

Approximately to the nearest hundredth = 7.87 minutes

Therefore, there will be 23mg of substance remaining after 7.87 minutes.

To learn more, visit the link below:

brainly.com/question/16624562

You might be interested in
PLEASE HELP ME I AM FAILING. I WILL GIVE BRAINLIEST
den301095 [7]

Answer:

3.

equation = \sqrt{7^2 + 12^2 } = c

Using:

\sqrt{a^2 + b^2 } = c or a^2 + b^2 = c^2 or

7^2 + 12^2 = c^2

49 + 144 = c^2

c^2 = 193

missing length = 13.9 inches

4. equation = \sqrt{24^2 + 32^2} = c

Using:

\sqrt{a^2 + b^2 } = c or a^2 + b^2 = c^2

24^2 + 32^2 = c^2

reduce to:

8 multiplied by everything:

3^2 + 4^2 = c^2

Since we know 3,4,5 is a Pythagorean triple, we can use this to find c.

Since c must be 5, we multiply by 8 since we divided by 8 earlier to get the 3,4,5 and get 40.

missing length = 40 inches

3 0
3 years ago
Evaluate 25 - 5e + 3/f when e = 4 and f = 3
Vitek1552 [10]
The answer is
4 I hope this helps 

5 0
3 years ago
1_9,644=100,000 to the nearest ten thousand
laiz [17]
119,644 is the answer I believe
7 0
3 years ago
Solve the system of linear equations<br><br> x + y = 4 and 2x + 3y = 0
forsale [732]

solve this answer by using substitution. set the first equation to x=-y+4 then substitute -y+4 for x in the second equation.

2(-y+4) + 3y=0

-2y+8 + 3y=0

y+8=0

y=-8

now use -8 and solve for x

x+(-8)=4

x=12

8 0
3 years ago
Your mother has a new cell phone. It comes with 18 applications already installed. She uses only "2" /"3" of those applications.
Slav-nsk [51]

Answer:

its 2/3(18) + 12 = 24

Step-by-step explanation:

3 0
3 years ago
Read 2 more answers
Other questions:
  • Complete the equation of the line through (6,-6) and (8,8)
    9·1 answer
  • Isabelle is mixing red paint with blue paint to make purple paint. She adds of a fluid ounce of red to of a fluid ounce of blue
    9·2 answers
  • Azizah got 1 for the slope of the line through 2 points (1,2) and (4,-1). Explain to her the mistake she made and how to find th
    10·2 answers
  • a person who weighs 120 lb on Earth would weigh 45 1/5 pounds on Mars set up a proportion to determine how much a 90 pound perso
    7·1 answer
  • What is the value of 12 more than the quiotent of a number of and two decreased by 4 when n is 4
    5·1 answer
  • Graph the set of points. which model is most appropriate for the set (-6 4) (-4 0) (-3 -2) (-1 -7)
    6·1 answer
  • 0.54 0.378<br> 0.54 divided by 0.378
    11·1 answer
  • A culture of bacteria has an initial population of 92000 bacteria and doubles every 7 hours. Using the formula P_t = P_0\cdot 2^
    15·1 answer
  • Marianne is completing a 4-mile route for
    12·1 answer
  • What is x equal to in the equation 10+x=5(1/5x+2)
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!