Please help me with this ASAP ASAP please please help

Answer:

The differential equation is [tex]\frac{dR}{dt} = -kR[/tex]

Step-by-step explanation:

Differential equation for the rate of change in radiation level:

Radiation level is R.

Rate of change indicates that the radiation level R varies in function of time t, which mathematically means that we have:

[tex]\frac{dR}{dt}[/tex]

After the reactor is shut down, the radiation from the nitrogen-17 decreases in such a way that the rate of change in the radiation level is directly proportional to the radiation level.

Rate of change is k. Decreases means that k is negative. Proportional to the radiation level of R means that -k multiplies R. So the differential equation is:

[tex]\frac{dR}{dt} = -kR[/tex]

Answer:

35 L

Step-by-step explanation:

because it cant be 1/4

Answer:

[tex]\frac{11}{20}[/tex]

Step-by-step explanation:

[tex]\frac{4}{5} - \frac{1}{4}[/tex]          Subtract the students who don't have protractors from the students who have mathematical instruments.

[tex]\frac{11}{20}[/tex]

9514 1404 393

Answer:

  3/5

Step-by-step explanation:

We assume that every student with mathematical instruments who hasn't lost their protractor will have a protractor.

If 1/4 of the students with instruments lost their protractor, then the remaining 3/4 of students with instruments still have their protractors. The fraction of the class with protractors is ...

  (3/4)(4/5) = 3/5

3/5 of the students in the class have protractors.

Answer:

B

Step-by-step explanation:

Answer:

Bill earns $220.00 in 22 weeks.

Step-by-step explanation:

If he is paid 20 dollars every 2 weeks for a car wash, we need to find out how many he gets for 22 weeks.

20 dollars = 2 weeks, to find 22, multiply both of the values by 11 to get to 22.

11(2 weeks = 20 dollars)

22 weeks = 220.

The amount of money earned in 22 weeks is $220.

Option D is the correct answer.

An expression is a way of writing a statement with more than two variables or numbers with operations such as addition, subtraction, multiplication, and division.

Example: 2 + 3x + 4y = 7 is an expression.

We have,

The amount for each car wash = $20

Number of car wash in two weeks = 1

Now,

Number of car washes in 22 weeks.

= 22 / 2

= 11

Now,

The amount earned in 11 car washes.

= 11 x 20

= $220

Thus,

Amount earned in 22 weeks is $220.

Learn more about expressions here:

https://brainly.com/question/3118662

#SPJ2

Answer: 10 out of 28 chancd

Step-by-step explanation:

Answer:

4/28

Step-by-step explanation:

trust me

Answer:

Step-by-step explanation:

Cross-multiply and solve for x:

Correct choice is C

Answer:

55 students

Step-by-step explanation:

all you do is 220*.25 and you get the answer

Answer:15

Step-by-step explanation:

Answer:  The value of the median is 15.

Step-by-step explanation:

1. Radius (r) of the sphere = 10 units. (Given)

• Surface area of the sphere = 4πr².

Surface area of the sphere = 4 × π × (10)²

Surface area of the sphere = 4 × π × 10 × 10

Surface area of the sphere = 400π units. (Ans)

And,

• Volume of the sphere = 4/3πr³.

Volume of the sphere = 4/3 × π × (10)³

Volume of the sphere = 4/3 × π × 10 × 10 × 10

Volume of the sphere = 4000π/3

Volume of the sphere = 1333.3π cubic units. [approx] (Ans)

__________________________________

2. Diameter of the sphere = 16 units. (Given)

Radius (r) of the sphere = 16/2 = 8 units.

• Surface area of the sphere = 4πr².

Surface area of the sphere = 4 × π × (8)²

Surface area of the sphere = 4 × π × 8 × 8

Surface area of the sphere = 256π units. (Ans)

And,

• Volume of the sphere = 4/3πr³.

Volume of the sphere = 4/3 × π × (8)³

Volume of the sphere = 4/3 × π × 8 × 8 × 8

Volume of the sphere = 2048π/3

Volume of the sphere = 682.6π cubic units. [approx] (Ans)

__________________________________

3. Radius (r) of the sphere = 5 units. (Given)

• Surface area of the sphere = 4πr².

Surface area of the sphere = 4 × π × (5)²

Surface area of the sphere = 4 × π × 5 × 5

Surface area of the sphere = 100π units. (Ans)

And,

• Volume of the sphere = 4/3πr³.

Volume of the sphere = 4/3 × π × (5)³

Volume of the sphere = 4/3 × π × 5 × 5 × 5

Volume of the sphere = 500π/3

Volume of the sphere = 166.6π cubic units. [approx] (Ans)

__________________________________

4. Diameter of the sphere = 18 units. (Given)

Radius (r) of the sphere = 18/2 = 9 units.

• Surface area of the sphere = 4πr².

Surface area of the sphere = 4 × π × (9)²

Surface area of the sphere = 4 × π × 9 × 9

Surface area of the sphere = 324π units. (Ans)

And,

• Volume of the sphere = 4/3πr³.

Volume of the sphere = 4/3 × π × (9)³

Volume of the sphere = 4/3 × π × 9 × 9 × 9

Volume of the sphere = 2916π/3

Volume of the sphere = 972π cubic units. (Ans)

__________________________________

Answer:

0.02

Step-by-step explanation:

i dont know if u want explanation

Answer:

a = 13

Step-by-step explanation:

a = 13

Answer:

constant: 4

coefficient:-5

variable:x

Step-by-step explanation:

You can easily search up the definition of each word and figure it out just saying. It's fine if u wanna do this-

Answer:

For question 1 it's B

For question 2 it's C

Step-by-step explanation:

For question 1, you have to apply the "Triangle Inequality Theorem"

A+B > C

B+C > A

A+C > B

Let's say that A=22, B=17, C= 14

22+17 > 14       True

17+14 > 22       True

22+14 > 17       True

Therefore, the answer is B

For question 2, you apply the rule of the sum of the triangles which is 180°

70+70+? = 180

140+? = 180

? = 40

Therefore, it's C

Answer:

y=-2x-7

Step-by-step explanation:

lines are typically written in y=mx+b form, where m is the slope and b is the y intercept

we are given the line y=1/2x-4

perpendicular lines are negative and reciprocal; if the slopes are multiplied together, the result is -1

so to find the slope of the new line, use this formula:

1/2m=-1

multiply by 2

m=-2

so the slope is -2

here's the equation so far, written in y=mx+b form

y=-2x+b

we need to find b

because the line passes through the point (-4,1), we can use it to solve for b

substiute -4 as x and 1 as y

1=-2(-4)+b

1=8+b

-7=b

so b is -7

therefore the line is:

y=-2x-7

Hope this helps! :D

Answer:

First Circle

Radius = 6

Diameter = 12

Circumference = 2 × [tex]\pi[/tex] × r = 2 × 3.14 × 6 = 37.68

2nd Circle

Radius = 3

Diameter =  6

Circumference = 2 × [tex]\pi[/tex] × r = 2 × 3.14 × 3 = 18.84

Hope This Helps!

Answer:

5%

Step-by-step explanation:

I didn't see any more than I HHHH

There are 20 total tosses.

1 was successful

P(4 heads)= 1/20

Experimental Probability = 1/20 * 100 = 0.05 * 100 = 5%

If you see more than one HHHH put the number that you count over 20 and multiply by 100.

Answer:

sorry sorry sorry sorry sorry

Answer:

I believe it should be feg

Answer:

9

Step-by-step explanation:

9 squared plus 40 squared= 41 squared

Answer:

D. A over 4

Step-by-step explanation:

One quarter is equal to [tex]\frac{1}{4}[/tex]. If her aunt is age 'a', than Salina's age is a/4

Hope this helps.

Answer:

D

Step-by-step explanation:

Its D because when you rotate 360 degrees you end up back where you were

Answer:

9

Step-by-step explanation:

3 3/4= 3.75.

3.75-2=1.75

1.75+5.5=7.25 or 7 1/4

7.25+1.75=9

Answer:

5

Step-by-step explanation:

[tex] \sqrt{ {(9 - 6)}^{2} + {(6 - 2)}^{2} } = \\ \sqrt{ {3}^{2} + {4}^{2} } = \\ \sqrt{25} = \\ 5[/tex]

Answer:

there have to be a number

Step-by-step explanation:

Here's the Answer,

the given outcome is an impossible event, because the sum of numbers can't be less than 2 hence, sum equal to 1 isn't possible.

And we know, the probablity of an impossible event is 0.

Answer:

[tex]C\left[\begin{array}{ccc}370\\228.5\\332\end{array}\right][/tex]

Answer:

C

Step-by-step explanation:

i have verified on the internet with other websites

Answer:

y=4

Step-by-step explanation:

in a 45-45-90 triangle sides a and b are equal and the hypotenuse is [tex]a\sqrt{2}[/tex]

so in this case y is a leg, so it is 4

in case there is a part two where they ask what x is, it would be [tex]4\sqrt{2}[/tex]