a radioactive substance has a half-life of 2 seconds. A scientist begins with a sample of 20 grams. How much of the substance remains after 8 seconds?

Answers

Answer 1

Answer:

1.25 g

Step-by-step explanation:

you start with 20g at 0 seconds.

divide by half after 2 seconds and you have 10g.

at 4 seconds you have 5g.

at 6 seconds you have 2.5g.

at 8 seconds you have 1.25g.

Answer 2

The size of the substance after 8 seconds will be 1.25 g

What is an expression?

The mathematical expression combines numerical variables and operations denoted by addition, subtraction, multiplication, and division signs.

Mathematical symbols can be used to represent numbers (constants), variables, operations, functions, brackets, punctuation, and grouping. They can also denote the logical syntax's operation order and other properties.

Given that a radioactive substance has a half-life of 2 seconds. A scientist begins with a sample of 20 grams.

Start with 20g at 0 seconds and divide by half after 2 seconds and you have 10g.

4 seconds you have 5g.

6 seconds you have 2.5g.

8 seconds you have 1.25g.

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Related Questions

Please help Please help

Answers

Answer:

with what

Step-by-step explanation:

3 t-shirts cost £25.95.
How much do 10 t-shirts cost?

Answers

Answer:

£86.50

Step-by-step explanation:

To find how much 10 t-shirts cost we have to find how much they cost individually.

3 T- Shirts / 25.95 = 8.65 which means that each T-Shirt Costs 8.65.

8.65 x 10 T-Shirts = £86.50

Please help, thank you (NO LINKS!)
Patsy has cheerleading practice every fourth day. She wants to be in the school play, but they have practice every sixth day. If both start on September 5th, what would be the next date she has to choose between cheerleading and play practice? Show your work and explain.

Answers

Answer:

the first time 4 and 6 intersent is 24

so 24 days after september 5th

september 29th

Hope This Helps!!!

how many miles did Candice bike on her route?

Answers

Answer:

200miles per hour andv50 9

Which equation represents a line which is parallel to y = 0?

A) y = 3
B) x = -8
C) y = x - 1
D) x = 4y

Answers

Answer:

y=3

Step-by-step explanation:

Horizontal Lines

To my knowledge the answer is c. As x is equal to 1 so therefore 1 - 1 = 0

(1,-1) (5,-7 find the slope

Answers

Answer:

m=-2

Step-by-step explanation:

m=-8/5-(1)

m=-8/4

divided -8 by 4

m=-2

Answer:

m=-2

Step-by-step explanation:

Help ASAP!!!!!
A. 1/4
​B. 4
C. - 1/4
​D. –4

Answers

Answer:

D. -4

Step-by-step explanation:

need help with math

Answers

Ah sorry I got it wrong, dear

B. 1/2

Explanation: 1/4 of grape juice as already in the bottle and then a mixture containing orange, grape and apple filled the bottle meaning the mixture was 3/4. If the mixture contained equal amounts of each juice it means 1/3 of each juice was in the mixture so 1/4 plus 1/4(the original amount of grape juice that was in the bottle before the mixture was added) is equal to 2/4 simplify that and you have 1/2

how many yards are there in 2 miles

Answers

Answer: 3520

please give brainliest

Step-by-step explanation:

Answer:

3,520 miles in a Yard.

Step-by-step explanation:

solve the median of 4,5,3,4,3,1

Answers

Answer:

arrange them in order = 1,3,3,4,4,5

then cancel them slowly from both side = 3,3,4,4

until u find a single number or two number.

for two number which is same as this do (3+4)/2 which is 7/2 = 3.5

Step-by-step explanation:

4,5,3,4,3,1 (n = 6)

[tex] \\ \tt median = \frac{n + 1}{2} [/tex]

[tex] \\ \tt \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = \frac{6 + 1}{2} [/tex]

[tex] \\ \tt \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = \frac{7}{2} [/tex]

[tex] \\ \tt \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = 3.5[/tex]

Find the surface area of a cube
with side length 8.5 cm.

Answers

Answer:   433.5 square cm

=========================================================

Explanation:

A cube has 6 identical faces, all of which are squares.

Each square has a side length of 8.5 cm, so its area is (8.5)^2 = 72.25 sq cm.

The overall surface area, aka the area of all 6 faces combined, is 6*72.25 = 433.5 square cm

Answer:

A=433.5cm²

Step-by-step explanation:

A=6a2=6·8.52=433.5cm²

WILL GIVE BRAINLIEST AND I SWEAR TO GOD IF ONE MORE BOT ANSWERS AND MAKES IT TO WHERE NO ONE ELSE CAN ANSWER


One challenge of federalism is that

power and authority are concentrated in the central government and can take away people’s rights
sometimes officials from different levels of government disagree on who should be in charge of a situation
local governments have the most power, which creates problems for trade with other nations
officials from state governments have too many rules to follow to be effective leaders

Answers

Answer:

local governments have the most power

Step-by-step explanation:

I hope this is right, but federalism gives more power to the state, so local governments could potentially have more power.

Answer:

i believe it is option one: power and authority are concentrated in the central government and can take away people’s rights

Step-by-step explanation: well i mean its true the governments are corrupted and are slowly taking away our rights

The circumference of a circle is 14.444 miles. What is the circle's diameter?

Answers

Answer:

2.29883

formula

[tex]c = 2 \times \pi \times r[/tex]

solving for (r) radius

[tex]r = \frac{c}{2\pi} = \frac{14.44}{2 \times \pi} [/tex]

= 2.29883

0.1 x 0.01 x 0.001
ans ???

Answers

>> Answer

________

[tex] \: [/tex]

[tex]0.1 \times 0.01 \times 0.001 = ...[/tex]

[tex] = \frac{1}{10} \times \frac{1}{100} \times \frac{1}{1.000} [/tex]

[tex] = \frac{1}{10 \times 100 \times 1.000} [/tex]

[tex] = \bold{ \frac{1}{1.000.000}} [/tex]

Answer:

[tex]0.1 \times 0.01 \times 0.001 = 0.000001 \\ \\ \\ \\ i \: hope \: it \: is \: helpfull[/tex]

if 20 articles cost $90,then the cost of 9 articles is

Answers

Answer:

$40.50

Step-by-step explanation:

90 divided by 20 is 4.5. then you multiply that times 9 and that's your answer.  

-
How many solutions does the equation 2 + 6(x - 4) = 3x - 18 + 3x have?

A)0
B)1
C)2
D) Infinite

Answers

Answer:

C because it's a quadratic equation and it can be solved by factorization and completing the square method and also general formula

Help with this problem pls!

Answers

Answer:

uh.. shii i dont know

Step-by-step explanation:

2 times a number less 4 is 20

Answers

Answer:

68?

Step-by-step explanation:

Answer:

The answer is 8

Step-by-step explanation:

Let the number be x

4x- 12=20 (12 less than 4 times a number is 20)

4x= 20 +12

4x=32

x=8

Hope this helps!!

write the equation of a line parallel to 2x+3y=12 that passes through the point (-3,4)

Answers

Answer:

[tex]y = \frac{-2}{3}x + 2[/tex]

Step-by-step explanation:

The first step is convert the given equation in a dependent and independent equation.

[tex]2x + 3y = 12[/tex]

[tex]3y = 12 - 2x[/tex]

[tex]y = 4 - \frac{2}{3}x[/tex]

[tex]x[/tex] is the independent variable and [tex]y[/tex] the dependent variable.

Since both lines are parallel the slope of both equations are the same

[tex]y = \frac{-2}{3}x + b[/tex]

Now for find the unknow [tex]b[/tex] replace the [tex]x[/tex] and [tex]y[/tex] fo the given point.

[tex]4 = (\frac{2}{3})3 + b[/tex]

[tex]4 = 2 + b[/tex]

[tex]4 - 2 = b[/tex]

[tex]2 = b[/tex]

So the final equation is equal to

[tex]y = \frac{-2}{3}x + 2[/tex]

Using the diagram and information below to find the measure of the missing angles. Don't forget to show your work and label your answer. Suppose mz1 = 105° 1/2 4 / 3 What are m22. m23 and mz4? mz2 = m23 = m24 =
please help (:​

Answers

Answer:

m∠2 = ______75__

m∠3 = ____105____

m∠4 = _____75___

Step-by-step explanation:

i did the math

if there was 200 kids= 100% and 43 of them left what is the percent

Answers

Answer:

It would be 86 as 43% of 200 is 86

Step-by-step explanation:

consider the expression
[tex] \sqrt{a^{2} + 12 } + |b| [/tex]
when a = -2 and b= 14. what is the value of the expression?

show work​

Answers

Answer:

18

Step-by-step explanation:

[tex]\sqrt{((-2)^2 + 12)} + 14[/tex]

= [tex]\sqrt{(4 + 12)} + 14[/tex]

= [tex]\sqrt{16}+14[/tex]

= 4 + 14

= 18

Hope this helps!

Answer:

[tex] \sf 18[/tex]

Step-by-step explanation:

[tex] \sf = \sqrt{ { - 2}^{2} + 12} + |14| [/tex]

[tex] \sf = \sqrt{(( - 2) \times ( - 2)) + 12} + 14[/tex]

[tex] \sf = \sqrt{4 + 12} + 14[/tex]

[tex] \sf = \sqrt{16} + 14[/tex]

[tex] \sf = \sqrt{ {4}^{2} } + 14[/tex]

[tex] \sf = 4 + 14[/tex]

[tex] \sf = 18[/tex]

can someone help
me on one of these please!

Answers

For number 13, there is no change. It is 0. The equation is x=7 since the line is on x and not y. The y intercept is 0.

Find a trinomial for the area of the rectangular rug shown on the right whose sides are x+2 feet and 3x-1 feet.

Answers

The trinomial for the rectangular rug is 3x² + 5x - 2

A polynomial is an expression consisting of the operations of addition, subtraction, multiplication of variables.

A trinomial is a polynomial with three terms.

The area of a rectangle = length * width

Area of rectangle = (x + 2) * (3x - 1) = 3x² + 6x - x - 2

Area of rectangle = 3x² + 5x - 2

The trinomial for the rectangular rug is 3x² + 5x - 2

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Find each missing measure in the diagram below.
EF=(
m2F=d
3.
232
18 in
23
E
E

Answers

Answer:

EF= 18 in. , m<F=134'

Step-by-step explanation:

This ones for the boys with the booming system, top down ac with the cooling sytem

PRETTY PLS HELP ME JUST 2 MORE QUESTIONS PLS 50 POINTS

Answers

Answer:

I think that you should take your time and answer, every one can help you

Step-by-step explanation:

Step-by-step explanation:

ok give question and intro new sis

8th Grade Math
Janelle is saving $6 per week to buy a new bike. she has $85 on week five. How do you write this in slope intercept form?

Answers

Let y-axis saving
X-axis weeks
Slope change in y-axis/x-axis
If at week 5 she has 85
85=6(5)+C
C=55
Y=6x+55

Identify the similar triangles.
ΔHFE=
ΔHFE=​

Answers

∆HFE is similar to ∆HFG and ∆ HEG (they all are right triangles and have the same, shape.)

The given triangle ΔHFE is similar to triangle GFH and triangle GHE.

What are similar triangles?

Similar triangles are two triangles that have the same shape but may differ in size. They have corresponding angles that are congruent and corresponding sides that are proportional.

Here,

Since triangle HFE is similar to triangle GFH,
∠HEF = ∠GHF,
∠FHE = ∠HGF, and ∠HFE = ∠HFG

Similarly

ΔHFE is similar to triangle ΔGHE.

Similar triangles are useful in many areas of mathematics and in the real world, such as in architecture, engineering, and cartography, where they are used to make scale models of buildings and other structures.

Thus, the given triangle ΔHFE is similar to triangle GFH and triangle GHE.

Learn more about similar triangles here:

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I want you to set a goal of signing up 25% of your new customers for our new service feature." Representative: "If I get 96 new customers that means I have to get

Answers

If he get 96 new customers that means he will have to sign 24 customers

for the new service features.

The deal is to get 25% of your new customer to sign the new service features.

When the new customers are 96 in numbers, the number of individuals(25%

of the new customers) to be signed for the new features can be calculated as

follows:

New customer to sign for the new features = 25% of 96

New customer to sign for the new features = 25 / 100 × 96

New customer to sign for the new features = 2400 / 100

New customer to sign for the new features = 24

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This means that if I get 96 new customers that means I have to get 24 new customers

From the question, I want to set a goal of signing up 25% of your new customers for our new service feature.

Since we have 96 new customers, hence the total amount of new customers needed will be expressed as:

= 25% of 96

= 0.25 * 96

= 24 new customers

This means that if I get 96 new customers that means I have to get 24 new customers

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What is the period of y=2cos(3x-2(3.14))?
A. 3(3.14)

B. 6(3.14)

C. 3(3.14)-2

D. 3(3.14)/3

Answers

Answer:

the correct answer is B

Step-by-step explanation:

I got it correct on 2021 edge

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