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

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.

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 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

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

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!

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

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

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

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]

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

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:

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.

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

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

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]

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.

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

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!

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!

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

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]

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

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

Answers

The answer to your question is C.2

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

Answers

Answer:

3−42+7+16

Step-by-step explanation:

if its simplify

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

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

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

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

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!

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]

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