solve pls brainliest

After x half-lifes, the amount of the isotope is:

A(x*T) = 90mg*e{-x*ln(2)}

And after 70 days, there are 5.628 mg

We define the half-life as the time such that the inital amount of a given substance reduces to half of it.

If the half-life is T, the amount of the substance can be written as:

A(t) = a*e^{-λ*t}

Where λ = ln(2)/T.

and a is the initial amount.

In this case, T = 17.5 days, then:

λ = ln(2)/17.5 days = 0.0396 / day

And we also have a = 90mg

Then the exponential equation is:

A(t) = 90mg*e^{-t*0.0396 / day}

After x half-lifes, the amount of the isotope left is:

A(x*T) = 90mg*e^{-x*T*ln(2)/T} = 90mg*e^{-x*ln(2)}

And after 70 days the amount is:

A(70 days) = 90mg*e^{-70 days*0.0396 / day} = 5.628 mg

If you want to learn more about exponential decays, you can read:

https://brainly.com/question/11464095

Answer:

Y=90mg(0.5)^5

1.86 after 70 days

Step-by-step explanation:

Answer:

c

Step-by-step explanation:

The distance I can see from the  top of the sears tower in Chicago is 46.41 mi.

The equation for direct proportionality = y = b√x

where:

b = y /√x

41 / √1135

b = 1.217

y = 1.217√1454

y = 46.41 mi

To learn more about direct proportion, please check: https://brainly.com/question/13742765

Answer:

6.25 weeks

Step-by-step explanation:

Take 18.75 and divide it by 3, since the crew is finishing 3 km per week. You get 6.25, so it took the crew 6.25 weeks to finish the road.

Hopefully this helps- let me know if you have any questions!

The basic formula for a circle is (x - h)^2 + (y - k)^2 = r^2, where the center is (h, k) and the radius is found by taking the square root.

h = 4

k = -2

Center: (4, -2)

square root of 9 = 3

Radius: 3

Correct Answer: C

Hope this helps!

Answer:

No, (-4, 6) is not a solution to y = -9.

Step-by-step explanation:

y= -9 has a horizontal line graph.  Every point on this line has -9 as its y-coordinate.  (-4, 6) does not lie on that line and is therefore not a solution to y = -9.

Using the combination formula, it is found that there are 84 ways to choose the three tiles.

The order in which the tiles are chosen is not important, hence the combination formula is used to solve this question.

[tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by:

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

In this problem, three tiles are chosen from a set of nine, hence:

[tex]C_{9,3} = \frac{9!}{3!6!} = 84[/tex]

There are 84 ways to choose the three tiles.

More can be learned about the combination formula at https://brainly.com/question/25821700

Answer:

D.

Step-by-step explanation:

Okay, so 8:15 to 12:00 is 225 minutes, or 3.75 hours

12:45 to 17:30 is 285 minutes, or 4.75 hours

3.75 + 4.75 = 8.5 hours (total)

She earns 14.50 dollars per hour

8.5 * 14.5 = 123.25 dollars

D.

Answer:

The answers is D: 8.5 hours x $14.50 = $123.25

Step-by-step explanation:

This employee worked a total of 8.5 hours on Monday (3.75 hours in the morning and 4.75 hours in the afternoon).

Then, you have to multiply the total amount of hours worked by the number of dollars paid per hour.

8.5 hours x $14.50 = $123.25

The number [tex]4.5*10^{-3}[/tex] is written in scientific notation whereas the rest of the numbers are not written in scientific notation.

Given numbers are:

1)[tex]4.5*10^{-3}[/tex]

2)[tex]14.5*10^{2}[/tex]

3)[tex]0.78*10^{-6}[/tex]

4)[tex]5.7*4^8[/tex]

Scientific notation is a way of writing very large or very small numbers. A number is written in scientific notation when a number between 1 and 10 is multiplied by a power of 10.

In the first number [tex]1 < 4.5 < 10[/tex] multiplied by [tex]10^{-3}[/tex]

As per the definition [tex]4.5*10^{-3}[/tex] is written in scientific notation.

The Rest of the numbers do not follow the definition of scientific notation so they are not in scientific notation.

Hence, the number [tex]4.5*10^{-3}[/tex] is written in scientific notation whereas the rest of the numbers are not written in scientific notation.

To get more about scientific notations visit:

https://brainly.com/question/1767229

Answer:

288 cm^3.

Step-by-step explanation:

The volume of each small  square = 2*2*2 = 8 cm^3

Each rectangular length of end 2*2 is made up of 12/2 = 6 squares.

There are  6 of these rectangular lengths.

So the volume = 6 * 6 * 8 cm^3

288 cm^3.

Answer:

Step-by-step explanation:

Slope intercept form

y + 7 = 3(x  + 4)                 Change all the double minuses to pluses.

y + 7 =  3x + 12                  Remove the brackets.

y + 7 - 7 = 3x + 12-7           Subtract 7 from both sides

y = 3x + 5

Slope

Whatever number is in front of the x is the slope Answer: 3

y intercept

Whatever comes after the plus sign (or minus sign) is the y intercept. It is a single number.  Answer: 5

x intercept.

This occurs when y = 0

0 = 3x + 5                      Subtract 5 from both sides

-5 = 3x + 5 -5

-5 = 3x                            Divide by 3

-5/3 = 3x / 3

-5/3 = x                          

Answer: x_intercept = -5/3

Based on the speed Alyssa used to get to London and the speed back to Boston, the average speed was 540 mph.

The average speed that Alyssa was going can be found by the formula:

= (Initial speed + Final speed) / 2

Solving gives:

= (480 + 600) / 2

= 1,080 / 2

= 540 mph

In conclusion, Alyssa's average speed was 540 mph.

Find out more on average speed at https://brainly.com/question/24739297.

Answer:

6 in

Step-by-step explanation:

4×12×w=288

48×w=288

/48. /48

w=6

Hey there!

This is the formula:

V=πr²h

V=π(7)²5

V=49π5

V=245π

V≈769.7 ft³(cubic feet)

Hope everything is clear.

Let me know if you have any questions!

Always remember: Knowledge is power!

The probability of winning a lottery by selecting the correct six integers from the positive integers not exceeding 50 is 6 × 10–8.

Probability is a measure of the likelihood of an event to occur. Many events cannot be predicted with total certainty.

The sample-set S consists of all combinations of 6 distinct elements of the set of 50 elements, and;

[tex]\rm |S| =C(50, 6)=\dfrac{50!}{44!6!}[/tex]

The winning event E ⊆ S is just one winning combination, so that

|E| = 1.

Therefore, the probability of winning a lottery is;

[tex]\rm P(E)=\dfrac{|E|}{|S|}\\\\ P(E)=\dfrac{1}{\dfrac{50!}{44!6!}}\\\\\\ P(E)=\dfrac{44!6!}{50!}\\\\ P(E)= 6 \times 10 {-8}[/tex]

Hence, The probability of winning a lottery by selecting the correct six integers from the positive integers not exceeding 50 is 6 × 10–8.

Learn more about probability here;

https://brainly.com/question/18162805

#SPJ4

A check register is also known as a cash disbursements journal, is a document that holds the record of all of the check and cash transactions that one's business has for an accounting period.

The kind of transactions that are recorded in a Check Register or a Cash Disbursement Journal are:

Do note that the register referenced in the questions is unavailable hence the general answer.

Learn more about Check Register at:
https://brainly.com/question/1082086

The amount Don must pay on his card without  going over the credit limit is $125.

Don's credit limit is $500. If Don does not want to go over the limit, he must not exceed the $500 limit. In order to determine the amount he should pay, add the sum of the charges and subtract it from the credit limit.

Amount to be paid = (425 + 200) - 500 = $125

To learn more about addition, please check: https://brainly.com/question/19628082

Answer:

A TRAPEZOID!!

Step-by-step explanation:

Answer:

Trapezoids have only one pair of parallel sides

Answer:

Correct option is A)

Given,a,b are distance roots of x

3

+3x

2

−1=0

⇒a

3

+3a

2

−1=0 and b

3

+3b

2

−1=0

let the third root be c

then c

3

+3c

2

−1=0

product of roots =

a

−d

=

1

−(−1)

=1

⇒

abc=1

c=

ab

1

but c is root of x

3

+3x

2

−1=0

⇒c

3

+3x

2

−1=0

⇒

(ab)

3

1

+

(ab)

2

3

−1=0

⇒

1+3ab−(ab)

3

=0

.....(1)

in equation (1)

(ab)

3

−3(ab)−1=0

⇒ab is root of

x

3

−3x−1=0

∴(ab) is root of

x

3

−3x−1=0

Answer:

sqrt(11)

Step-by-step explanation:

a^2+b^2 = c^2

a = 5

c = 6

b = ?

25 - b^2 = 36

36 - 25 = b^2

b = sqrt(11)

The ladder should be 7.81 feet long.

Pythagoras theorem tell us the relation between the sides of a right-angled triangle, it states, the sum of the squares of the base and perpendicular is equal to the square of the hypotenuse.

Given that, Aubrey is building a slide for her kids. If the ladder is 6 feet tall, and she wants the bottom of the slide to be 5 feet from the ladder,

This slide is in the form of a right triangle, therefore applying the Pythagoras theorem, we have,

a²+b² = c² (refer to the figure attached)

5²+6² = c²

c² = 25+36

c² = 61

c = √61

c ≈ 7.81

Hence, the length of the slide should be 7.81 feet.

For more references on Pythagoras theorem, click;

https://brainly.com/question/343682

#SPJ2

Increased concentration is the answer as drug impairs our ability to control ourselves.

Hope it helps!

Impaired brain function as a result of drug use doesn't involve: Option D: Increased concentration.

A significant deterioration in one or more domains of conscious mental activity, such as language, learning, and memory, that interferes with everyday function and independence are some of the traits of impairment of brain.

Thus, as we see, first three options are showing acts of impaired brain but the fourth option contradicts, as impairment from drug use isn't going to increase concentration and if it somehow does, then it isn't impairment.

Thus, impaired brain function as a result of drug use doesn't involve: Option D: Increased concentration.

Learn more about impaired brain function here:

https://brainly.com/question/7451329

Finding perimeter is simple. All you do is add up all of the side lengths, and bada bing bada boom, you got the perimeter.

Answer:

5

Step-by-step explanation:

Median from 24 to 28

Median from 28 to 34

Interquartile range

Answer:

volume = 138 cm³

Step-by-step explanation:

Equation

volume of a prism = base area × height

Given:

Substituting given values into the equation:

⇒ volume = 23 × 6

                 = 138 cm³

Using the Central Limit Theorem, it is found that the mean of the sampling distribution is of 78 and the standard deviation is of 2.84.

It states that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].

In this problem, for the population, we have that [tex]\mu = 78, \sigma = 11[/tex].

Then, considering samples of n = 15, we have that the standard deviation is given by:

[tex]s = \frac{11}{\sqrt{15}} = 2.84[/tex].

More can be learned about the Central Limit Theorem at https://brainly.com/question/24663213

The area of a rectangle is l*w. We have the length as 4.5 in and we can find the width by doing 3+2+4.5 = 9.5 in.

Then, we multiply them. 4.5*9.5 = 42.75 inches²