Situation:
Find the substance's half-life, in days.
• Round your answer to the nearest tenth.
A 25 gram sample of a substance that's
used for drug research has a k-value of
0.1229.
Enter the correct answer.
N = Noe
-kt
DONE
No = initial mass (at time t = 0)
?
N = mass at time t
k = a positive constant that depends on
the substance itself and on the units
used to measure time
t = time, in days

Answers

Answer 1

Answer:

5.6 days

Step-by-step explanation:

We are given;

Initial Mass; N_o = 25 g

Mass at time(t); N_t = 25/2 = 12.5 (I divide by 2 because we are dealing with half life)

k = 0.1229

Formula is given as;

N_t = N_o•e^(-kt)

Plugging in the relevant values;

12.5 = 25 × e^(-0.1229t)

e^(-0.1229t) = 12.5/25

e^(-0.1229t) = 0.5

(-0.1229t) = In 0.5

-0.1229t = -0.6931

t = -0.6931/-0.1229

t = 5.6 days


Related Questions

The perimeter of a rectangular piece of plastic is 30 millimeters. The area is 54 square millimeters. What are the dimensions of the piece of plastic?

Answers

Answer:

6 mm and 9 mm are the dimensions of the piece of plastic.

Step-by-step explanation:

Keep in mind the formulas for the area and perimeter of a rectangle:

A = lw

P = 2 (l + w)

List the factors of 54:

1, 2, 3, 6, 9, 18, 27, 54

POSSIBLE DIMENSIONS of the piece of plastic:

1 mm and 54 mm:

Area - 54 mm^2

Perimeter - 110 mm

2 mm and 27 mm

Area - 54 mm^2

Perimeter - 58 mm

3 mm and 18 mm

Area - 54 mm^2

Perimeter - 42 mm

6 mm and 9 mm

Area - 54 mm^2

Perimeter - 30 mm

The rectangular piece of plastic with the dimensions 6mm and 9 mm corresponds with the area and perimeter of the piece of plastic mentioned. So these are the correct dimensions.

Hope this helps!

Ms. Dawson’s call did a science experiment. The class started out with 650 bacteria cells. The growth rate predicted was 4.5%. Sketch the graph that represents the situation. Label the y-intercept and the point that represents the projected bacteria population 30 h from the start of the experiment. Round to the nearest whole number.

Answers

Answer:

your slope would be 4.5.... so go up 4 and to the right 5. the y-intercept is 650 so that is where your line would start instead of at 0... hope this helped :)

Step-by-step explanation:

The exponential function gotten from the table is given by y = 650(1.045)ˣ

Exponential function

An exponential function is in the form:

y = abˣ

where y, x are variables, a is the initial value of y and b is the multipliers.

Let y represent the bacteria population after x hours.

The class started out with 650 bacteria cells.

a = 650

Growth rate = 4.5%

b = 100% + 4.5% = 104.5% = 1.045

The exponential function gotten from the table is given by y = 650(1.045)ˣ

After 30 hours:

y = 650(1.045)³⁰ = 2434

Find out more on exponential function at: https://brainly.com/question/12940982

Lines s and t are parallel and r is a transversal.

Which angles are congruent to 4?
a) 2, 5, 8
b) 3, 5, 7
c) 2, 6, 8
d) 3, 7, 2

Answers

Answer:

The angles that are congruent to 4 are: 3, 8, and 7.

3 and 4 are vertical angles, 8 and 3 are opposite interior angles, 8 and 7 are vertical angles.

Hope this helps!

Help mee whats the answerr :( Q: The midpoint of the line segment with the coordinates (9, -8) and (-2, 1) is _

Answers

Answer:

(3.5, - 3.5)

Step-by-step explanation:

Using the Midpoint theorem, we have

x=(9-2)/2=7/2=3.5

y=(-8+1)/2=-7/2=-3.5

will mark brainliest! determine if this is a one solution, no solution, or infinite solution equation

Answers

No solution. The x’s cancel out which leaves you with ( (1/2) =150). So that is not true which means no solutions

Please help explanation if possible

Answers

Answer:

y = 3x+6

Step-by-step explanation:

refer to the picture

Answer:

y = 3x + 6

Step-by-step explanation:

The equation of a line in slope- intercept form is

y = mx + c ( m is the slope and c the y- intercept )

y = 3x + 2 ← is in slope- intercept form

with slope m = 3

Parallel lines have equal slopes, so slope of parallel line is 3

Expressing the equation in point- slope form with m = 3 , (x₁, y₁ ) = (1, 9)

y - 9 = 3(x - 1)

y - 9 = 3x - 3 ( add 9 to both sides )

y = 3x + 6 ← in slope- intercept form

pls help answer, explain it too. I will give brainliest

Answers

Pages read by Arnold in 7 minutes = 3 pages

Pages read by Arnold in 1 minutes

= 3/7 pages

= 6/14 pages

Pages read by Brenda in 14 minutes = 8 pages

Pages read by Brenda in 1 minutes = 8/14 pages

(6/14) < (8/14)

So, speed of Arnold < speed of Brenda.

So, Brenda reads faster.

pls help me due tomorrow

Answers

Answer:

Step-by-step explanation:

f(x) = 2x - 4

g(x) = 1/2x - 4

6)

f(4) means that wherever you see an x on the right, you put a 4.

f(4) = 2x - 4

f(4) = 2*4 - 4

f(4) = 8  - 4

f(4) = 4

7)

g(x) = 1/2x - 4

g(2) = 1/2(2) - 4

g(2) = 1 - 4

g(2) = - 3

8)

f(-5) = 2*-5  - 4

f(-5) = -10 - 4

f(-5) = -14

9)

g(-6) = 1/2 ( - 6) - 4

g(-6) = -3 - 4

g(-6) = - 7

Find the circumference and the area of a circle with diameter equal to 8.6 inches. Use 3.14 for pi

Please answer it will mean a lot thanks

Answers

Answer: Circumference of circle = 27.004 inches

              Area of circle = 58.0586 inches²

Step-by-step explanation:

Diameter of circle = 8.6 inches

Pi ([tex]\pi[/tex]) = 3.14

Circumference of circle (With diameter) = [tex]\pi \\[/tex]d ([tex]\pi[/tex]×diameter)

                                                                = 3.14 × 8.6

                                                                = 27.004 inches

Area of circle (With diameter) = [tex]\pi[/tex][tex]d^{2}[/tex]/4

                                                 = 3.14 × 8.6 × 8.6 / 4

                                                 = 3.14 × 73.96 / 4

                                                 = 58.0586 inches²

if i traveled 35 miles on his bike in 3.5 hours what is his rate of speed? i rlly need help- m not sure how to do the steps or whatever

Answers

Answer:

hes going 10 miles an hour,

Step-by-step explanation:

if it took you 3.5 hrs and you went 35 miles, you can do 35/3.5=10, which is 10 miles an hour

Answer:

10 miles per hour

Step-by-step explanation:

We know that distance = rate * time

35 miles = rate * 3.5 hours

Divide each side by 3.5 hours

35 miles / 3.5 hours = rate

10 miles per hour = rate

I have two identical dice with the numbers
-1, 2, -3, 4, -5 and 6
I roll my dice and work out my total.
Which of the following totals cannot be achieved?
a) 3
b) 7
c) 8

Answers

Answer:

7 cannot be achieved

-1 + 6 = 5

-3 + 4 = 1

-5 + 2 = -3

as you can see, no combinations can form seven

find the missing side lengths​

Answers

Answer:

[tex]x = \frac{2 \sqrt{3} }{3} [/tex]

[tex]y = 1[/tex]

Step-by-step explanation:

30, 60, 90 triangle

URGENT ! HELP ME I WILL MARK YOU BRAINLIEST !!!!

pleasee fasterrr !!!!​

Answers

Answer:

3b (3a - 4b)

Step-by-step explanation:

Answer:

C

Step-by-step explanation:

9ab - 12b² ← factor out 3b from each term

= 3b(3a - 4b) → C

Help solve for the area

Answers

Answer:

B

Step-by-step explanation:

half × base × height

height × length

Answer: B

Step-by-step explanation:

Triangle)

25 - 7 = 18

[tex]A=\frac{1}{2}(b)(h)\\A=\frac{1}{2}(18)(17)\\A=153cm^2[/tex]

Rectangle)

[tex]A=b(h)\\A=7(17) = 119cm^2[/tex]

Total)

[tex]153+119=272 cm^2[/tex]

Which of the following choices is a linear function?
O f(x) = x2 – 3x+ 2
O f(x) = 3x3 – 3x + 2
O f(x) = -3x + 2

Answers

Answer:

f (x) = x2 - 3x + 2

Step-by-step explanation:

Answer:

f(x)=-3x+2

Step-by-step explanation:

The first one is a quadtratic function because it is in quadtratic form.

The second one is also not linear because it looks like a squiggly line. Sorry I forgot what they are called but I know it is not linear.

That leaves the last one is is linear and should be going down because there is a negative in front of the coefficient. It also has so exponent to prove why it is linear even further.

Hope this helps!

A staircase is being constructed in a new house as displayed on the right. Each tread is 18 cm and each riser is 10cm. Determine the angle of inclination of the stairs.

Answers

Answer:

29.1°

Step-by-step explanation:

Given that :

Riser, AB, Opposite = 10 cm

Thread, = AC, Adjacent = 18 cm

Angle of inclination, θ

Using trigonometry :

Tan θ = opposite / Adjacent = AB / AC

Tan θ = 10 / 18

θ = tan^-1(10/18)

θ = 29.055

Hence, angle of inclination is 29.1° (1 decimal place)

If f(x)=-2x find x= -1

A.-3
B.-2
C.2
D.0

Answers

The answer to your question is C.2

Can you help please please helps

Answers

Answer:

2nd option

Step-by-step explanation:

Given

- np - 6 ≤ 3(c - 5) ← distribute

- np - 6 ≤ 3c - 15 ( add 6 to both sides )

- np ≤ 3c - 9

Divide both sides by - p , reversing the symbol as a result of dividing by a negative quantity.

n ≥ [tex]\frac{3c-9}{-p}[/tex]

(f^3-5f+25)-(4f^2-12f+9)

Answers

Answer:

3−42+7+16

Step-by-step explanation:

if its simplify

plss i reallly need help


Answers

Answer:

7x^2 +7x

------------------

x^2 -9

Step-by-step explanation:

7x          (x+1)

------- * ----------

(x+3)    (x-3)

Multiply

7x^2 +7x

------------------

x^2 +3x-3x-9

7x^2 +7x

------------------

x^2 -9

Answer:

7x^2 +7x   /   x^2 -9

Step-by-step explanation:

77 yd
36 yd
What is the length of the hypotenuse?
C =
yards

Answers

Answer:

c = 85 yd

Step-by-step explanation:

Using Pythagoras' identity in the right triangle.

The square on the hypotenuse is equal to the sum of the squares on the other 2 sides , that is

c² = 77² + 36² = 5929 + 1296 = 7225 ( take square root of both sides )

c = [tex]\sqrt{7225}[/tex] = 85

Answer:

[tex]85yd[/tex]

Step-by-step explanation:

According to PYTHAGORAS Theorem,

[tex] {c}^{2} = {77}^{2} + {36}^{2} \\ {c}^{2} = 5929 + 1296 \\ {c}^{2} = 7225 \\ c = \sqrt{7225} \\ c= 85yd[/tex]

find the value of x. give reasons to justify your answer NEED HELP ASAP!!!!

Answers

Answer:

[tex]x = 34^\circ[/tex]

Step-by-step explanation:

Note that ∠TSU and ∠PSR are vertical angles. Hence:

[tex]m\angle TSU = m\angle PSR[/tex]

∠PSR is the sum of ∠PSQ and ∠QSR. Hence:

[tex]\displaystyle m\angle TSU = m\angle PSQ + m\angle QSR[/tex]

We know that ∠TSU measures 4x and ∠QSR measures 3x. Thus:

[tex](4x) = m\angle PSQ + (3x)[/tex]

Solve for ∠PSQ:

[tex]m\angle PSQ = x[/tex]

Next, ∠PQS and ∠RQS form a linear pair. Thus:

[tex]m\angle PQS + m\angle RQS = 180^\circ[/tex]

∠RQS measures 68°. Thus:

[tex]m\angle PQS +(68^\circ) = 180^\circ[/tex]

Solve for ∠PQS:

[tex]m\angle PQS = 112^\circ[/tex]

The interior angles of a triangle must total 180°. So, for ΔPQS:

[tex]\displaystyle m\angle SPQ + m\angle PQS + m\angle PSQ = 180^\circ[/tex]

Substitute in the known values:

[tex](x) + (112^\circ) + (x) = 180^\circ[/tex]

Simplify:

[tex]2x = 68^\circ[/tex]

And divide. Hence:

[tex]x = 34^\circ[/tex]

A father is 51 years old and his son is 19. How many years ago was the father 5 times his son's age? ​

Answers

Answer:

x=11

Step-by-step explanation:

51-x-5*19= -5x

51-5*19= -4x

4x=5*19-51

4x=95-51

4x=44

x=11

Step-by-step explanation:

let x year ago son age was 5 time his father age.

age of son before x year = 19-x

age of father before x year = 51-x

NOW

according to the question

5(19-x) =51-x

95-5x =51-x

95-51 = -X-5x

44 = 4x

x=11

so your ans is 11years ago

What are the roots of this equation x^2-4x+9=0?

Answers

Answer:

Roots is a fancy word for zero, which is also another fancy word for the x intercept.

You can factor a quad or use the quadratic equation to get zeros.

In this case, its non-factorable. So you gotta use the quadratic.

Using the quadratic equation you get : x = -2 ± √-1 (√5),

which can be rewritten as x = -2 ± i(√5)

Function was : x^2 + 4x + 9

For quad, I identified the following:

A = 1

B = 4

C = 9

I also added a picture of the formula in the attached.

I need 26/50 simplified so I can answer an assignment

Answers

Answer:

13/25

Step-by-step explanation:

Find: 26/50 simplified

Step 1: Find the GCF (Greatest Common Factor) of 26 and 50

26: 1, 2, 13 & 26

50: 1, 2, 5, 10, 25 & 50

The GCF (Greatest Common Factor) will be 2

Then simplify 26/50 by 2

26/50 = 13/25

One fifth of a number is subtracted from one fourth of the number,the result is 8 more than 10.Find the number

Answers

Answer:

4

Step-by-step explanation:

Let the number be x.

According to the question,

[tex]\dashrightarrow \sf { \dfrac{1}{4}x - \dfrac{1}{5}x= 8 + 10 } \\[/tex]

[tex]\dashrightarrow \sf { \dfrac{5x + 4x}{2}= 18 } \\[/tex]

[tex]\dashrightarrow \sf { \dfrac{9x}{2}= 18 } \\[/tex]

[tex]\dashrightarrow \sf { 9x = 18 \times 2 } \\[/tex]

[tex]\dashrightarrow \sf { 9x = 36 } \\[/tex]

[tex]\dashrightarrow \sf { x =\cancel{ \dfrac{36}{9} }} \\[/tex]

[tex]\dashrightarrow \underline{\boxed{\pmb { \frak {x = 4 }}}} \\[/tex]

The number is 4.

l= 6 ft, w = 2 ft, h= 5 ft what is the surface area of the rectangular prism​

Answers

it’s literally 6x2x5 (60 sq ft)

104 ft^2

Explanation:

The surface areaa of a rectangular prism is given by the formula:

2 (lw + hl + hw)

l = length

w = width

h = height

Substitute the formula with the givsn dimensions:

2 ([6 x 2] + [5 x 6] + [5 x 2])

= 2 (12 + 30 + 10)

2 (52)

= 104

So the SA is 104 square feet or ft^2

Hope this helps!

Thomas went for a long hike and burned 675 calories in 2 hours. Marvin decided to go for a bike ride and burned 1,035 calories in 3 hours. Who burned the most calories per hour? Let t represent Thomas's calories burned and m represent Marvin's calories burned. Equivalent Ratio 1: Equivalent Ratio 2: burned the most calories per hour.

Answers

Step-by-step explanation:

I am not sure I fully understand what your teacher wants from you, but I would say we only need to define the burning rate per hour for both people, and with that normed rate (number / hour) we can answer the main question directly.

Thomas burned 675 cal/ 2 hours.

by dividing to and bottom by 2 (it is important to do the same action on the top and the bottom to keep the value of the ratio unchanged) we get

337.5 cal / hour

and Marvin burned 1035 cal / 3 hours.

so, the same trick, this time dividing to and bottom by 3 to norm the whole ratio to a 1 hour baseline :

345 cal / hour

so, Marvin burned more calories per hour.

Each cat at the animal shelter gets
5/6 pound of food. Allie has 9 1/2
pounds of cat food. How many cats
can Allie feed?
A: 7
B:9
C: 11
D:13

Answers

Answer: C : 11

Step-by-step explanation:

5/6 is 0.833


So divide 9 1/2 by 5/6

So the answer is 11,4 and it round off to 11



So the answer is 11 option C

slove for inequality of -6> t-(-13)

Answers

Step-by-step explanation:

-6>t-(-13)

= -6>t+13

= -6-13>t

= -19>t

= t<-19

Answer:

t < - 19

Step-by-step explanation:

Given

- 6 > t - (- 13) , that is

- 6 > t + 13 ( subtract 13 from both sides )

- 19 > t , then

t < - 19

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