Strontium-90 has a half-life of about 28 years. Which equation will solve the problem of how many grams of a 40 g sample
will remain after 84 years?
Oy = }(40)
y = {(40)
Oy = 40(1)
y = 40()
84

Answers

Answer 1

Answer:a0 = 40 mg

a1 = 20 mg  after 28 years

a2 = 10 mg  after another 28 years

Step-by-step explanation:Set this up as

10 = 40 (1/2)t/28

and solve for t in years.

10/40 = (1/2)t/28

log(0.25) = (t/28) log(0.5)

t = 28 log(0.25) / log(0.5) years = 56 years

Answer 2

Answer:

40 mg

Step-by-step explanation:

10 = 40 (1/2)t/28   and solve for t in years.   10/40 = (1/2)t/28   log(0.25) = (t/28) log(0.5)   t = 28 log(0.25) / log(0.5) years = 56 years


Related Questions

Turner has 6 pounds of pasta. Each time he makes dinner he uses 0.75 pound
of pasta. How many dinners can he make?
Your answer

Answers

Answer:

8

Step-by-step explanation:

if you have 6 pounds and you use 0.75 pounds per then you can make 6/0.75 dinners = 8

find the area of right-andled triangled whose sight-angled
making side are 3cm and 4cm​

Answers

Answer:

3*4=12

Step-by-step explanation:

what is 92 Times 37

Answers

Answer:

3404

Step-by-step explanation:

92 x 37 = 3404

Which of the following theorems verifies that abc wxy

Answers

Answer:

C.    AA

Step-by-step explanation:

Since m<Y = 27°, then m<W = 27°.

We have two angles of one triangle (A and B) congruent to two angles of the other triangle (W and X).

Answer: C.   AA

If carpet costs $24.61 per square yard and is available in whole square yards only, find the cost of carpeting the three bedroom floors in the accompanying floor plan.

Answers

Answer:

Step-by-step explanation:

The area of each bedroom is the product of its length and width.

  Bdrm 1 area = (14 ft)×(14 ft) = 196 ft²

  Bdrm 2 area = (11 ft)×(12 ft) = 132 ft²

  Bdrm 3 area = (12 ft)×(11 ft) = 132 ft²

Then the total area of carpet needed is ...

  196 ft² +132 ft² +132 ft² = 460 ft²

There are 9 ft² in each square yard, so the number of square yards needed is ...

  (460 ft²)/(9 ft²/yd²) = 51.11... yd²

Since we can only obtain whole square yards, 52 square yards are needed. The cost of that will be ...

  (52 yd²)×($24.61/yd²) = $1279.72

The cost of carpeting for the three bedrooms will be $1279.72.

To compare the teaching methodologies of two of its eighth-grade math teachers, a school decides to compare student test scores from the two classes throughout the year.

Which type of statistical study is the school conducting?

a) Matched-pair design study
b) Meta-analysis
c) Retrospective observational study
d) Prospective observational study

Answers

Answer:

D) Prospective observational study

Step-by-step explanation:

A study which gathers data moving forward is called a prospective study.  Since the data is gathered on students without controlling the setting moving forward, it is a prospective observational design.

Find the value of each expression.


30 ÷ 3 × 2

Answers

Answer:

Step-by-step explanation:

1) First division has to be done.

2) After that multiplication has to be done.

30 ÷ 3 * 2 = 10 * 2

                 = 20

Answer:

20

Step-by-step explanation:

30 ÷ 3 × 2

(Since it’s division and multi platoon, we just go left to right)

10 × 2

20

U (24 win Q7 A gardener needs to order fertiliser for a piece of land. The piece of land is a square with sides measuring 8 metres. This formula shows how many grams of fertiliser she needs. grams of fertiliser needed = length in metres x width in metres x 25 The supplier sells these bags of fertiliser. 10K 5kg 2kg 1kg 1 kilogram 2 kilograms 5 kilograms 10 kilograms Which bag of fertiliser should the gardener order? Include figures to explain your answer. Show all your working.​

Answers

Answer:

first: there is a problem in the question in de mentioned quantity u mentioned 10k instead of (10kg).

Step-by-step explanation:

add all your 1uantity afteru divide by 8

Answer:

one fertilizer bag from weight of two kilograms

Step-by-step explanation:

Grams of fertilizer needed = Length in meters * Width in meters * 25

                                            = 8 * 8 * 25

                                            = 1600 grams

Kilograms of fertilizer needed = 1600 / 1000

                                                 = 1.6 kilograms

Therefore, gardener can order 1 fertilizer bag with weight of 2kilpgrams.

m∠AFD=90° . m∠AFB=31°. Find m∠DFE.
A. 87
B. 29.5
C. 31
D. 28

Answers

Answer:

D. 28

Step-by-step explanation:

Given:

m∠AFD = 90°

m∠AFB = 31°

Required:

m∠DFE

Solution:

m<AFB = m<CFD (both angles are marked as congruent angles)

Since m<AFB = 31°, therefore,

m<CFD = 31°

m<AFB + m<CFD + m<BFC = m<AFD

Plug in the known values

31° + 31° + m<BFC = 90°

62° + m<BFC = 90°

Subtract 62° from each side

m<BFC = 90° - 62°

m<BFC = 28°

m<BFC = m<DFE = 28° (both angles are marked congruent to each other)

Therefore,

m<DFE = 28°

Help question 25 pleasee

Answers

Answer:

4b³ + 11b² - 6b + 13

Step-by-step explanation:

Subtract like terms.

6b³ - 2b³ = 4b³

3b² - (-8b²) = 3b² + 8b² = 11b²

0 - 6b = -6b

8 - (-5) = 13

All together, the difference is 4b³ + 11b² - 6b + 13.

10a+5(a-3)=15 I don’t know the answer I keep checking and it’s wrong

Answers

Answer:

[tex]10a + 5(a - 3) = 15 \\ 10a + 5a - 15 = 15 \\ 15a = 30 \\ a = \frac{30}{15} \\ a = 2 \\ 10 \times 2 + 5(2 - 3) = 15 \\ 20 + - 5 = 15 \\ 15 = 15 \\ lhs = rhs\\ thank \: you[/tex]

Answer: a = 2

Solve:

Given

10a + 5 (a - 3) = 15

Expand parentheses and apply the distributive property

10a + 5 · a - 5 · 3 = 15

10a + 5a - 15 = 15

Combine like terms

(10a + 5a) - 15 = 15

15a - 15 = 15

Add 15 on both sides

15a - 15 + 15 = 15 + 15

15a = 30

Divide 15 on both sides

15a / 15 = 30 / 15

[tex]\boxed{a=2}[/tex]

Check:

Left-hand side = 10a + 5 (a - 3)

Left-hand side = 10(2) + 5 (2 - 3)

Left-hand side = 20 + 5(-1)

Left-hand side = 20 - 5

Left-hand side = 15

Right-hand side = 15

15 = 15, therefore, [tex]\boxed{a=2}[/tex] would make the equation true.

Hope this helps!! :)

Please let me know if you have any questions

sequence 32,52,72,92 simplified​

Answers

Step-by-step explanation:

the common increment is 20

Answer:

8, 13, 18, 23

Step-by-step explanation:

This one is confusing

Answers

Answer:

it s just asking for negative d

Step-by-step explanation:

Answer:

D(-1) = 2

Step-by-step explanation:

replace x with D(x), which in this case is -1

D(x) = x²-2x-1

replace x with -1

D(x) = (-1)²-2(-1)-1

Now solve using PEMDAS

guys pls tell me this answer as soon as possible​

Answers

que es un cuadrilatero

Write an algebraic expression that represents three less than the square of a number k.

Answers

Answer:

2k-3

Step-by-step explanation:

the square of k is k times k so 2k (two times k) and less than three means minus three.

Two professional gamers subscribe to twitch streamers. Jonah has 430$ saved up, and spends 45$ a month on
subscriptions. Rodrick has 310$ saved up, and spends 25$ a month on subscriptions.
A) Create an equation that can be used to find m, the number of months it will take for both gamers to have the
same amount of money left?
B) After how many months will the gamers have the same amount of money?

Answers

Answer:

A) [tex]430-45m = 310-25m[/tex]

B) 6 months

Step-by-step explanation:

A) for Jonah, the equation would be [tex]430-45m[/tex]

Because the money is being spent on the subs, you subtract that from his original savings.

The same thing is said for Rodrick, but his equation would be [tex]310-25m[/tex]

to find out the number of months it will take for both gamers to have the

same amount of money left, you set their equations equal to each other:

[tex]430-45m = 310-25m[/tex]

B) you solve for m.

[tex]430-45m = 310-25m[/tex]

first by subtracting 310 on both sides to get:

[tex]430-310-45m=-25m[/tex]

[tex]120-45m=-25m[/tex]

then add 45m on both sides because we cant have negative months

[tex]120=-25m+45m[/tex]

[tex]120=20m[/tex]

divide by 20 on both sides to get the number of months

[tex]\frac{120}{20} =\frac{20m}{20}[/tex]

[tex]m=6[/tex]

Identifying properties used to solve liner equation.
Options are:
Addition property of Equality
subtraction property of Equality
multiplication property of Equality
division property of Equality
simplifying
distributive

Answers

Need a better explaination

Please help

Solve the inequality.
-1 < 2x + 5 < 4
[?] sxs H

Answers

Answer:

-1-5<2x+5-5<4-5

-6<2x<-1

-3<x<-1/2

please help solve for y!

Answers

As both angles are supplementary

[tex]\\ \Large\sf\longmapsto 3x+(2x+3y)=180°[/tex]

[tex]\\ \Large\sf\longmapsto 3x+2x+3y=180[/tex]

[tex]\\ \Large\sf\longmapsto 5x+3y=180[/tex]

[tex]\\ \Large\sf\longmapsto 3y=180-5x[/tex]

[tex]\\ \Large\sf\longmapsto y=\dfrac{180-5x}{3}[/tex]

And

[tex]\\ \Large\sf\longmapsto 3x=90[/tex]

[tex]\\ \Large\sf\longmapsto x=\dfrac{90}{3}[/tex]

[tex]\\ \Large\sf\longmapsto x=30[/tex]

Now

Putting value

[tex]\\ \Large\sf\longmapsto y=\dfrac{180-5x}{3}[/tex]

[tex]\\ \Large\sf\longmapsto y=\dfrac{180-5(30)}{3}[/tex]

[tex]\\ \Large\sf\longmapsto y=\dfrac{180-150}{3}[/tex]

[tex]\\ \Large\sf\longmapsto y=\dfrac{30}{3}[/tex]

[tex]\\ \Large\sf\longmapsto y=10[/tex]

Can you please help me with this question

Answers

Answer:

Where is the question?

Step-by-step explanation:

Python is an interpreted high-level general-purpose programming language. Python's design philosophy emphasizes code readability with its notable use of significant indentation.

a word problem on proportions using a unit rate
Lashonda made $273 for 13 hours of work.
At the same rate, how many hours would she have to work to make $231?
hours
Х
?

Answers

eleven hours -  11 hours

She would have to work 11 hours to make $231.

Step 1: 273/13 = 21
So, x equals 21

Step 2: 231/21 = 11

write your answer as an integer or as a decimal rounded to the nearest tenth​

Answers

Answer:

8.6

Step-by-step explanation:

VW = WX / cos (36°)

= 7 / 0.81

= 8.6

Answer:

8.65

Step-by-step explanation:

cos 36° = 7 / VW

VW = 7 /  cos 36°

VW = 8.65

A principal of $4000 is placed in a savings account at 6% per annum compounded annually. How much interest is earned in the account after three years

Answers

The interest earned in the account after three years is $720.

The formula for simple interest= P×T × R/100

Principal (P) = $4000

Time( T) = 3 years

Rate(R) = 6%

interest(I)= 4000×3 × 6/100

I = 72000 ÷ 100

I = 720

Therefore, the interest earned in the account after three years is $720.

Learn more about simple interest here:

https://brainly.com/question/19705587

Question 1 of 10
Is (0,0) a solution to this system?
A. No. (0,0) does not satisfy either inequality.
B. No. (0,0) satisfies y< x2 + 2x + 1 but does not satisfy yz x2 + x - 4.
C. No. (0,0) satisfies ya x2 + x - 4 but does not satisfy y< x2 + 2x + 1.
O
D. Yes. (0,0) satisfies both inequalities.

Answers

Answer:

D

Step-by-step explanation:

0=> 0+0-4, 0=>-4 TRUE

0<0+0+1, 0<1 TRUE

Ginny writes down a secret number on her palm. She says that it is a three-digit even number. The units digit is 1 more than the hundreds digit. The tens digit is twice the sum of the units digit and the hundreds digit.

Answers

Answer:

Hello,

Answer 162

Step-by-step explanation:

Let say n the searched number.

[tex]n=\overline{abc}\\a>0\\c=a+1\\b=2*(a+c)\\\\.T.\ means\ True.\\\\\\\begin{array}{c|c|c|c}a&c&b&ok\\1&2&6&.T.\\3&4&14&.F.\\5&6&22&.F.\\7&8&30&.F.\end{array}\\\\\\\boxed{Answer\ n=162}\\[/tex]

Put the following equation of a line into slope-intercept form, simplifying all
fractions.
3x + 6y = -42

Answers

Answer:

y = -1/2x -7

Step-by-step explanation:

3x + 6y = -42

Slope intercept form is

y = mx+b where m is the slope and b is the y intercept

Subtract 3x from each side

3x-3x+6y = -3x-42

6y = -3x-42

Divide each side by 6

6y/6 = -3x/6 - 42/6

y = -1/2x -7

What is the Square root of 30 ,12,36

Answers

Answer:

the square root of:

30: 5.477225575

12: 3.464101615

36: 6 <-- explanation of square root: any number that when multiplied by itself equals your wanted number (in this case 36) will be the square root of your wanted number.

Please if anyone can help me

Answers

I am unable to see the picture ( if you have one) try re uploading and I can help

Complete the table. Round your entries to the
nearest thousandth.
a
b
C
dz
ex
ASAP

Answers

a=2,5937

b=2,7048

c=2,7181

d=2,7183

e=2,7183


If f(x) = 3x + 10 and g(x) = 2x - 4, find (f+ g)(x).

Answers

Answer:

5x+6

Step-by-step explanation:

f(x) = 3x + 10

g(x) = 2x - 4

(f+ g)(x)= 3x + 10 +  2x - 4

Combine like terms

           = 5x+6

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