Element X is a radioactive isotope such that every 26 years, its mass decreases by half. Given that the initial mass of a sample of Element X is 390 grams, how long would it be until the mass of the sample reached 260 grams, to the nearest tenth of a year?​

Answers

Answer 1

Answer:

It will take 15.029 years for element X to reach mass of 260 grams

Step-by-step explanation:

The half life period of radioactive element X is 26 years

The initial mass of radioactive element X is 260 grams

Elapsed time = half life * log (beginning amount /ending amount)/log 2

Substituting the given values, we get

Elapsed time = 26 * log (390/260)/log 2

=  15.209 years


Related Questions

How do we solve this in factor form? X^2-11x+24=0

Answers

Answer:

x=8, 3

Step-by-step explanation:

24 has 8 factors: 1,2,3,4,6,8,12,24

8 and 3 make 11

If you factor it out, the equation is (x-8)(x-3)=0

to get 0, only one of the expressions has to equal 0

so x can have 2 different values

Calculate the number of edges of the solid. Given it has 8 faces; 4 hexagons & 4 triangles

Answers

Answer:

20 Edges

Step-by-step explanation:

As this figure shows only 10 edges..so to meet the given condition (8 faces; 4 hexagons & 4 triangles) same figure is present at the back making total of 20 Edges.

Please help me with this ASAP ASAP please please help please please

Answers

Answer:

Step-by-step explanation:

Base perimeter: 5 x 2 x π = 10π

LA = 10π x 2 = 20π

Base area : 5^2π = 25π

SA = 25π x 2 + 20π = 70π

V : 25π x 2 = 50π

On a coordinate plane, a line goes through (negative 4, 0) and (4, negative 4). A point is at (2, 3).
What is the equation of the line that is parallel to the given line and passes through the point (2, 3)?

x + 2y = 4
x + 2y = 8
2x + y = 4
2x + y = 8

Answers

9514 1404 393

Answer:

  (b)  x +2y = 8

Step-by-step explanation:

The only offered line that includes the given point is ...

  x +2y = 8

__

We can check the other choices:

  x + 2y = 2 +2(3) = 2+6 = 8 . . . matches B (not A)

  2x +y = 2(2) +3 = 4+3 = 7 . . . . not a choice

_____

Getting there from scratch

The standard form equation for a line can be written from ...

  (y2 -y1)x -(x2 -x1)y = constant

  (-4 -0)x -(4 -(-4))y = constant . . . . using the given points (-4, 0) and (4, -4)

  -4x -8y = constant

For standard form, we need the leading coefficient to be positive, and we need common factors removed. We can get there by dividing by -4.

  x +2y = constant

The value of the constant will be whatever it takes for the given point to lie on the line. For (x, y) = (2, 3) to be a solution, we must have ...

 x +2y = (2) +2(3) = constant = 8

The desired line has the equation ...

  x +2y = 8

Answer:

B on edge

Step-by-step explanation:

The number of mold spores on a piece of bread after a different amount of time or listed in the table below

Which function models the number of mold spores on the bread after X days

Answers

Answer:

Option (4)

Step-by-step explanation:

From the table attached,

Ratio of spores in day 2 and day 1 = [tex]\frac{400}{200}[/tex]

                                                         = 2

Ratio of spores in day 3 and day 2 = [tex]\frac{800}{400}[/tex]

                                                          = 2

There is a common ratio of 2 in each successive to the previous term of the Mold spores.

Therefore, spores are growing exponentially.

Let the function representing exponential function is,

y = a(b)ˣ

Here, y = Number of spores after time 'x'

x = Number of days

a and b are the constants.

On day 1,

x = 1

y = 200

By substituting these values in the exponential function,

200 = a(b)¹

ab = 200 -------(1)

On day 2,

x = 2

y = 400

400 = a(b)² -------(2)

Divide equation 2 by equation 1,

[tex]\frac{400}{200}=\frac{ab^{2} }{ab}[/tex]

b = 2

By substituting the value of b in equation (1),

a(2) = 200

a = 100

Therefore, equation of the function will be,

y = 100(2)ˣ

Option (4) will be the answer.

Could someone help me figure this out??

Answers

Answer:

180

Step-by-step explanation:

Which is bigger? 2^4 or 4^2?​

Answers

Answer:

Both are equal

Step-by-step explanation:

[tex]2^4 = 16 \\ \\ {4}^{2} = 16 \\ \\ \implies \: {2}^{4} = {4}^{2} [/tex]

Answer:

Step-by-step explanation:

2^4=16 and 4^2=16

They both equal the same thing so im guessing neither. They are both the same value.

Hope this helped!

PLS let me know if i'm wrong so i can correct my mistake!!

PLEASE ANSWER ILL GIVE BRIA LIEST

Answers

Answer:B

Step-by-step explanation:

The answer is letter.... D

What is the perimeter?? Please help!

Answers

Step-by-step explanation:

perimeter of the given figure=24cm+24cm+30cm+20cm+20cm+20cm+5cm+5cm

=148cm

Answer:

148mm aka 1.48cm aka 1cm48mm

Step-by-step explanation:

to obtain the small thing between the"24mm" and"20mm":

(30mm-20mm)÷2

=5mm

so add up all those given information:

24mm+24mm+20mm+20mm+20mm+30mm+5mm+5mm

comment below if you still don't get it ;)

How many moles are present in 4.51x1015 atoms of Aluminum (Al)?

Answers

Answer:

divide by avagadro number to get the amount of moles in the atoms you have

what is the area of the triangle 16, 10, 8

Answers

Answer:

480

Step-by-step explanation:

(16x10x8) divided by 2 = 480

WITH THE STEPS
FOR THE 2 SHAPE

Answers

Answer:

70 in

Step-by-step explanation:

7 * 7 = 49 {that's the square}

(7 * 6) * 1/2 = 21 {that's the triangle}

49 + 21 = 70

Answer:

the square SxS= 7x7 = 49

the triangle is hxs÷2=(7×6 )÷2 =42 ÷2 = 21

Find the minimum value of
C = 2x + 3y subject to the following constraints:

(4x + 3y > 29
X + 2y 11
x20
y > 0
C = [?]

Answers

Answer C=[19]


x+2y>=11 (*4)
=> 4x+8y>=44 and 4x+3y>=29
=> 5y>=15
=> y>=3 => 3y>=9
x>=11-2y => x>=5 => 2x>=10
=> 2x+3y>= 19
C=[19]

I need help fast!!!
Please

Answers

Answer:

B

Step-by-step explanation:

A rectangle is 4 times as long as it is wide. If the area is 64 square feet, find its perimeter

Answers

Answer:

40 feet

Step-by-step explanation:

long sides are 16

short sides are 4

Perimeter is l + l + w + w

so 16 + 16 + 4 + 4

= 40

The perimeter of the given rectangle is 40 feet.

What is the perimeter of a rectangle?

The perimeter of a rectangle is defined as the sum of all the four sides of the rectangle.

The perimeter of a rectangle = 2( l + b)

It is given that rectangle is 4 times as long as it is wide. If the area is 64 square feet,

The area is 64 square feet = l x w

So,

The long sides are 16

The short sides are 4

Perimeter = 2 (l + w)

Perimeter = 2( 16  + 4)

Perimeter = 40

Learn more about the area;

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Which of the following equations will produce the graph shown below?

Answers

Answer:

x-1/8y^2=0

Step-by-step explanation:

just took the test

Find the height of ABD

Answers

Answer:

[tex]Height=\boxed{10\sqrt{2}} [/tex]

[tex] Area =\boxed{165\sqrt{2}} [/tex]

Step-by-step explanation:

By geometric mean theorem:

[tex] AC=\sqrt{25\times 8}[/tex]

[tex] AC=\sqrt{5^2 \times 2^2 \times 2}[/tex]

[tex] AC=5\times 2\sqrt{2}[/tex]

[tex] AC=10\sqrt{2}[/tex]

So,

[tex]Height=\boxed{10\sqrt{2}} [/tex]

[tex] Area = \frac{1}{2} \times base\times height [/tex]

[tex] \therefore Area = \frac{1}{2} \times (25+8)\times 10\sqrt{2} [/tex]

[tex] \therefore Area =33\times 5\sqrt{2} [/tex]

[tex] Area =\boxed{165\sqrt{2}} [/tex]

Two imaginary roots
A.144
B.O
D.-4
C.36

Answers

Answer:

D) -4 (with imaginary roots ±2i)

Step-by-step explanation:

Since you cannot take the square root of a negative number to produce a real result, the only option that has two imaginary roots is D) -4, where the two imaginary roots are 2i and -2i.

A die is rolled. What is the probability of getting an even number?
A. 1/6
B. 1/2
C. 1/3
D. 1/4

Answers

Answer:

I wanna say 1/3 because there 3 even numbers on a dice

Step-by-step explanation:

What’s the correct answer for this question?

Answers

Answer:

$16 is correct answer

Hope it helps you

Answer is 16
Step-by-step exploration:
One CD lets be x
Five CDs - 5x
5x=80
x=80/5=16

Answer plz due in a few min

Answers

Answer:

40

Step-by-step explanation:

24^2+32^2=c^2

square root of 1600 is 40

Answer:40

Step-by-step explanation:Because

a^2 + b^2=c^2

What is the slope of the line that passes through (5,4) and (7,10)?

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

Answers

I think it’s A using the formula y2-y1/x2-x1

Answer:

A. 3

Step-by-step explanation:

I just did it on a calculator and got it correct

HELP WILL GIVE BRANLIEST

Answers

Answer:

The answer would be B  [tex]120ft^{3}[/tex]

Step-by-step explanation:

volume of triangular prism is 30 and volume of the cube is 90 :)

n 2019, approximately 97.4% of all the runners who started the Boston Marathon (in Boston, Massachusetts, USA) were able to complete the 42.2 km (26.2 mile) race. If 100 runners are chosen at random, find the probability that at least 5 of them did not finish the marathon

Answers

Answer:

0.1199 = 11.99% probability that at least 5 of them did not finish the marathon

Step-by-step explanation:

For each runner, there are only two possible outcomes. Either they finished the marathon, or they did not. The probability of a runner completing the marathon is independent of any other runner. This means that the binomial probability distribution is used to solve this question.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]

In which [tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.

[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]

And p is the probability of X happening.

97.4% finished:

This means that 100 - 97.4 = 2.6% = 0.026 did not finish, which means that [tex]p = 0.026[/tex]

100 runners are chosen at random

This means that [tex]n = 100[/tex]

Find the probability that at least 5 of them did not finish the marathon

This is:

[tex]P(X \geq 5) = 1 - P(X < 5)[/tex]

In which

[tex]P(X < 5) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4)[/tex]

[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]

[tex]P(X = 0) = C_{100,0}.(0.026)^{0}.(0.974)^{100} = 0.0718[/tex]

[tex]P(X = 1) = C_{100,1}.(0.026)^{1}.(0.974)^{99} = 0.1916[/tex]

[tex]P(X = 2) = C_{100,2}.(0.026)^{2}.(0.974)^{98} = 0.2531[/tex]

[tex]P(X = 3) = C_{100,3}.(0.026)^{3}.(0.974)^{97} = 0.2207[/tex]

[tex]P(X = 4) = C_{100,4}.(0.026)^{4}.(0.974)^{96} = 0.1429[/tex]

[tex]P(X < 5) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4) = 0.0718 + 0.1916 + 0.2531 + 0.2207 + 0.1429 = 0.8801[/tex]

[tex]P(X \geq 5) = 1 - P(X < 5) = 1 - 0.8801 = 0.1199[/tex]

0.1199 = 11.99% probability that at least 5 of them did not finish the marathon

What is the measure of DEF

Answers

The calculated measure of the arc DEF is 204 degrees

Calculating the measure of arc DEF

From the question, we have the following parameters that can be used in our computation:

The circle

The measure of the arc intercepted by the angle DEF is calculated as

Arc DF = 2 * DEF

When the given values are substituted in the above equation, we have the following equation

Arc DF = 2 * 78

So, we have

Arc DF = 156

The measure of arc DEF is then calculated as

Arc DEF = 360 - 156

Evaluate

Arc DEF = 204

Hence, the measure of the arc DEF is 204 degrees

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Solve for x using
cross multiplication.
X + 8
-
3x – 2
8
3
x = [?]

Answers

Answer:

x=70

Step-by-step explanation:

(x+8)*8=(3x-2)*3

8x+64=9x-6

x=70

what is 8w+5=4(2w+1)

Answers

Answer:

No solution

Step-by-step explanation:

1. Distribute the right side.

8w+5=8w+4

2. This has no solution.

Find the value of x in the diagram below( HELP PLEASE)

Answers

9514 1404 393

Answer:

  x = 30

Step-by-step explanation:

The sum of exterior angles of a convex polygon is 360°. Here, that means ...

  3x° +x° +2x° +2x° +4x° = 360°

  12x = 360

  x = 360/12 = 30

The value of x is 30.

Answer:

Solution :-

Sum of all angles = 360⁰

[tex] \to \sf \: 2x + 2x + x + 4x + 3x = 360[/tex]

[tex] \to \: 12x = 360[/tex]

[tex] \to \: x = \dfrac{360}{12} [/tex]

[tex] \sf \: x = 30[/tex]

A company wanted to estimate the mean lifetime of its new model of lightbulbs. They use a method for testing bulbs that accelerates the process so the bulbs burn out relatively quickly, and the company can accurately calculate the corresponding lifetime under regular usage. They took a random sample of 555 of these new bulbs and calculated their lifetimes. Here are the data and summary statistics:

Bulb 1 2 3 4 5
Lifetime 14.2 12.2 13.4 12.6 14.6
Mean= 13.4 years
Standard deviation= sx =1.02 years

Required:
Wrtite a 90% confidence interval for the mean lifetime in years) for this type of bulb.

Answers

Answer:

13.4±2.132(1.02/5)

Step-by-step explanation:

Khan Academy

The confidence interval for the mean life time is; CI = 13.4 ± 3.678(1.02/5)

What is the confidence interval?

Formula for confidence interval is;

CI = x' ± z(s/√n)

We are given;

Mean; x' = 13.4

Standard deviation; s = 1.02

Sample size; n = 5

z-score at confidence level of 90% = 1.645

Thus;

CI = 13.4 ± 1.645(1.02/√5)

CI = 13.4 ± 3.678(1.02/5)

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Find the volume of the figure. Round to the nearest hundredth if necessary. (Figure is not to scale)


Answers

Answer:

360 mi^3

Step-by-step explanation:

The figure is composed by two parallelepipeds. For find the volume we have to find the volume of both the solids and the added up the two values

solid  1

length = 11 - 4 = 7 mi

base area = length x width = 7 x 4 = 28 mi^2

V = base area x height = 28 x 6 = 168 mi^3

solid 2

base area = 8 x 4 = 32 mi^2

V = 32 x 6 = 192 mi^3

total volume: 168 + 192 = 360 mi^3

The volume of the figure is 360 mi³.

What is Volume?

Volume of a three dimensional shape is the space occupied by the shape.

Given is a figure where two rectangular boxes are put on top of each other.

Volume of a rectangular prism = L × W × H

Here L is the length, W is the width and H is the height.

The dimensions of the rectangular prism are :

Larger one having L = 11 mi, W = 6 mi and H = 4 mi

Smaller one on top having L = 4 mi, W = 6 mi and H = 8 - 4 = 4 mi.

Volume of the figure = volume of larger box + Volume of smaller box

                                  = (11 × 6 × 4) + (4 × 6 × 4)

                                  = 264 + 96

                                  = 360 mi³

Hence the volume of the figure is 360 mi³.

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