I neeeddddd help on this I’m failing

Answer:

The half-life of this radioactive substance is of 8.6 months.

Step-by-step explanation:

Exponential decay of an amount:

The equation that models an amount after t units of time, subject to exponential decay, is given by:

[tex]A(t) = A(0)(1-r)^t[/tex]

In which A(0) is the initial amount and r is the decay rate, as a decimal.

A radioactive substance decays to 30% of its original mass in 15 months.

This means that [tex]A(15) = 0.3A(0)[/tex]. We use this to find 1 - r.

[tex]A(t) = A(0)(1-r)^t[/tex]

[tex]0.3A(0) = A(0)(1-r)^{15}[/tex]

[tex](1-r)^{15} = 0.3[/tex]

[tex]\sqrt[15]{(1-r)^{15}} = \sqrt[15]{0.3}[/tex]

[tex]1 - r = (0.3)^{\frac{1}{15}}[/tex]

[tex]1 - r = 0.9229[/tex]

So

[tex]A(t) = A(0)(0.9229)^t[/tex]

Determine the half-life of this radioactive substance to the nearest tenth.

This is t for which A(t) = 0.5A(0). So

[tex]A(t) = A(0)(0.9229)^t[/tex]

[tex]0.5A(0) = A(0)(0.9229)^t[/tex]

[tex](0.9229)^t = 0.5[/tex]

[tex]\log{(0.9229)^t} = \log{0.5}[/tex]

[tex]t\log{0.9229} = \log{0.5}[/tex]

[tex]t = \frac{\log{0.5}}{\log{0.9229}}[/tex]

[tex]t = 8.6[/tex]

The half-life of this radioactive substance is of 8.6 months.

Answer:

Step-by-step explanation:

Let's simplify step-by-step.

(k+1)(x2)−8kx+3k+5

Distribute:

=(k)(x2)+(1)(x2)+−8kx+3k+5

=kx2+x2+−8kx+3k+5

Answer:

=kx2−8kx+x2+3k+5

Answer:

Step-by-step explanation:

8 is not a function

9 is a function

10 is a function

Answer:

A. A triangle can be equilateral and obtuse at the same time

Step-by-step explanation:

All angles in an equilateral triangle are 60° therefore they cannot be above 90° and less than 180°

9514 1404 393

Answer:

  7x^3 +11x^2 -5x -8

Step-by-step explanation:

Combine like terms.

  (4x^3+6x^2+2x^2-3) + (3x^3+3x^2-5x-5)

  = (4 +3)x^3 +(6 +2 +3)x^2 +(-5)x + (-3 -5)

  = 7x^3 +11x^2 -5x -8

_____

Noting that the first expression contains two x^2 terms, we wonder if you actually want the sum ...

  (4x^3+6x^2+2x-3) + (3x^3+3x^2-5x-5)

  = (4 +3)x^3 +(6 +3)x^2 +(2 -5)x +(-3 -5)

  = 7x^3 +9x^2 -3x -8

Answer:

y intercept: [tex]y = 1[/tex]

x intercept: [tex]x = -1[/tex] and [tex]x = -3[/tex]

Step-by-step explanation:

Given

The attached graph

Solving (a): The y intercepts

This is the point where [tex]x = 0[/tex]

From the attached graph, [tex]x = 0[/tex] when

[tex]y = 1[/tex]

Hence, the y intercept is 1

Solving (b): The x intercepts

This is the point where [tex]y = 0[/tex]

From the attached graph, [tex]y = 0[/tex] when

[tex]x = -1[/tex] and [tex]x = -3[/tex]

Hence, the x intercept are -1 and -3

Answer:

∆ RPQ

Step-by-step explanation:

__________________

Answer:

5.0 =x

Step-by-step explanation:

Since this is a right triangle

tan theta = opp side/ adjacent side

tan 50 = x / 4.2

4.2 tan 50 = x

5.005365089 =x

Rounding to the nearest tent

5.0 =x

Answer:

0.1771

Step-by-step explanation:

total number of cards in a deck : 52

number of face card per suite : 3

total number of suites : 4 (hearts, clubs, diamonds, spades)

3 * 4 = total number of face cards

12/52 = 0.23 = probability of drawing a face card

remaining card are non face cards

52-12 = 40

40 non face cards

40/52 = 0.77 = probability of drawing a non face card

probability of drawing a face card followed by a non face card

multiply probabilities together to find combined probability

probability of drawing a face card * probability of drawing a non face card

= 0.23 * 0.77

= 0.1771

Answer:

See the attachment ⬆️⬆️

Answer:

The distance between the two towns is of 1000 km.

Step-by-step explanation:

This question is solved by proportions, using a rule of three.

We have that:

3 cm represents a distance of 400 km.

What is the distance represented by 7.5 cm?

3 cm - 400 km

7.5 cm - x km

Applying cross multiplication:

[tex]3x = 400*7.5[/tex]

[tex]x = \frac{400*7.5}{3}[/tex]

[tex]x = 1000[/tex]

The distance between the two towns is of 1000 km.

The answer goes here,

a) We have to tell the time and day which simone has to tell her sister, for picking her up from airport.

b) We have given the day (monday), time(7:00 pm) and total time to reach the destination(18 hours).

c) No such formula will be used here, we will just use our mental ability to solve this question.

d) She will leave at 7:00 pm, day has 24 hours. So, she will be in the flight on monday:

= 24 - (12 + 7) ----------- [12 here means the time of rest of the day,(morning to noon)]

= 24 - 19

= 5 hours

So, she will complete 5 hours of her destination on monday,now the time left is:

= 18 - 5

= 13

= (12 + 1 )hours

So, on tuesday, she will be in the flight for 12 hours (noon) and then on 1:00 pm she will reach the airport, as she needs and extra hour to plane so, the final time is 1:30 pm. And finally, the time she should tell her sister is 1.30 pm.

76+2x=180

180-76=2x

104=2x

X=52

Answer:

x=52

Step-by-step explanation:

360=76+90+90+2x

2x=360-256

x=104/2

x=52

Answer:

8.4%

Step-by-step explanation:

let x = interest rate

55,000(1 + x)^16 = 200,000

divide both sides by 55,000

(1 + x)^16 = 3.636

find the invese of 16

1 + x = 1.084

x = 0.084

x = 8.4

Answer:

The answer is D

Hope this helps!

Brainliest??

Answer:

D

Step-by-step explanation:

the answer is D because if she already made 7 she need to add n to 7 to get 40 or greater

Answer:

54 in³

Step-by-step explanation:

9×3×2 = 54 in³

_______

Answer: 3900[tex]\pi[/tex] ft^3

if you use the formula on how to find the volume of a cone

V=[tex]\pi[/tex]r^2*h/3

you will insert 30 where the r is, 13 in where h is, after you just solve that and your answer would be 3900[tex]\pi[/tex] ft^3

Answer:

A.5+4<9+1

B. 5+4<10+0

C. 5+4>5-4

D. 5+4=15-4

Step-by-step explanation:

A. 9<10

B. 9<10

C. 9>1

D9=9

Answer:

A=10>5+4

B=10>5+4

C=1<5+4

D=11>5+4

Step-by-step explanation:

Answer:

The probability of you choosing S would be a 1/11 chance or a 0.0909090909 chance.

Answer:

1 / 11

Step-by-step explanation:

there are 11 letters in candlesick so 11 possibilities and 1 S which is 1 out of 11 or 1 / 11.

Hope this helps ( :

Answer:

what is the question?

Step-by-step explanation:

Answer:

i answered

Step-by-step explanation:

Answer:

37.7

Step-by-step explanation:

Circumference = [tex]2\pi r[/tex]

Circumference = [tex](2)(\pi )(6)[/tex]

Circumference = 37.69911184 / 37.7

Therefore, circumference of the circle with the radius 6 cm is 37.7.

Answer:

37.7

Step-by-step explanation:

formula for circumference of a circle=2πr

2×π×6=37.7cm

Answer:

too much salt will not bring taste to the cup cakes

Step-by-step explanation:

Answer:

Step-by-step explanation:

11 no

46+4x=90 degree(being perpendicular)

4x=90-46

x=44/4

x=11

12 no

They are complementary angles

6 no

angle B+27=180 degree(being straight line)

angle B=180-27

angle B=153

10 no

angle 38 +angle DFE=180 degree(being supplementary)

angle DFE=180-38

angle DFE=142 degree

5 no

They are vertically opposite angles.

7 no

angle AGF and angle CGD (because they have common arm and vertex)

Answer:

Solution given:

11.4x+46=90[being right angle]

4x=90-46

x=44/4

x=11

12.

Complementary angles

5.

vertical

6.

<ABD+27=180°[linear pair]

<ABD=180-27

<ABD=153° degree

10.

<DFE+38=180[being supplementary]

<DFE=180-38

<DFE=142 degrees.

7.

angle DGE and angle DGC

8.

<AGB and <AGE

Answer:

2/5 :)

Step-by-step explanation:

58+2=60+25=85-25=60 60 = 2/5

The solution is 5/17

The probability that the next customer will pay with a debit card is given by the equation A = 5/17

What is Probability?

The probability that an event will occur is measured by the ratio of favorable examples to the total number of situations possible

The value of probability lies between 0 and 1

Given data ,

Let the probability that the next customer will pay with a debit card be A

Now , the equation will be

The number of customers who paid cash last week = 58 customers

The number of customers who used debit card last week = 25 customers

The number of customers who used credit card last week = 2 customer

So ,

The total number of customers = 58 + 25 + 2

The total number of customers = 85 customers

Now , the probability that the next customer will pay with a debit card A = number of customers who used debit card last week / total number of customers

Substituting the values in the equation , we get

Probability that the next customer will pay with a debit card A = 25 / 85

On simplifying the equation , we get

Probability that the next customer will pay with a debit card A = 5 / 17

Therefore , the value of A is 5/17

Hence , the probability is 5/17

To learn more about probability click :

https://brainly.com/question/17089724

#SPJ2

Answer:

I think C. is it

Step-by-step explanation:

Answer:

[tex] \frac{(x - 2)(x + 2)}{x - 8} [/tex]

Answer: I asked my teacher, she said it is c

Step-by-step explanation:

Answer:

yes it's c

have a great day

Answer:

Length of Line AC = 26 units

Step-by-step explanation:

Given:

Line AC = [3x + 1] + 8

Line BC = [x - 2] + 2

Find:

Length of Line AC

Computation:

Line AB ║ Line L

So,

Using Mid-Point theorem;

[3x + 1] / 8 = [x - 2] / 2

2[3x + 1] = 8[x - 2]

6x + 2 = 8x - 16

8x - 6x = 16 + 2

2x = 18

x = 9

So,

Line AC = [3x + 1] + 8

Line AC = [3(9) + 1] + 8

Line AC = [27 + 1] + 8

Line AC = 28 + 8

Length of Line AC = 26 units

Answer:

18.5 i believe

Step-by-step explanation:

sorry if im wrong, have a great day!!