Suppose the half-life of a certain radioactive substance is 20 days and there are 50g present initially.
a)
Write an equation that models this situation.
b)
How much radioactive substance is remaining after 12 days?
c)
Find the time when there will be 1g of the substance remaining.

Answers

Answer 1

Answer:

a)   10(5g + 2r)   weight loss over time

b)   20/12 = 1.66667 = 50 / 1.67 = 29.999 gm = 5(6g -1/50)  or  5(5 + g) = 30g

c) 30g = 12 days = 3/5   therefore 5/5 -3/5 = 2/5  = 2/5 x 50 (g) = 20g in 8 days lost

8/20 = 0.4  loss each day 50g - 0.8g = 20-2 = 18 days.

Step-by-step explanation:


Related Questions

Which expression is the sum of
-5.3m + 3.4n and 2.5n + 2.8m?
A. -2.8m + 6.2n
B. -2.5m + 5.9n
C.-8.1m + 0.9n
D. 2.5m + 5.9n
+
B

Answers

Answer:

b

Step-by-step explanation:

its b because you add the 3.4n +2.5n then you subtract -5.3+2.8

Expression Name
Expression
E
–8 + 4∕7
F
7 – 0.5
G
9 + (–3)
H
3.8 – 6.7

The table above shows four numeric expressions. Which expression is an integer when it's evaluated?

Answers
A)

H

B)

F

C)

E

D)

G

Answers

Answer:

G

Step-by-step explanation:

9+(-3) = 6

The diagram shows a logo​

Answers

Answer/Step-by-step explanation:

✔️Find EC using Cosine Rule:

EC² = DC² + DE² - 2*DC*DE*cos(D)

EC² = 27² + 14² - 2*27*14*cos(32)

EC² = 925 - 756*cos(32)

EC² = 283.875639

EC = √283.875639

EC = 16.85 cm

✔️Find the area of ∆DCE:

Area = ½*14*27*sin(32)

Area of ∆DCE = 100.15 cm²

✔️Since ∆DCE and ∆ABE are congruent, therefore,

Area of ∆ABE = 100.15 cm²

✔️Find the area of the sector:

Area of sector = 105/360*π*16.85²

Area = 260.16 cm² (nearest tenth)

✔️Therefore,

Area of the logo = 100.15 + 100.15 + 260.16 = 460.46 ≈ 460 cm² (to 2 S.F)

use the rule to write the first five terms of the pattern: Rule: add 8, subtract 4 First term: 13​

Answers

Answer:

17

Step-by-step explanation:

13 + 8 - 4

Answer:

{13, 17, 21, 25, 29}

Step-by-step explanation:

Add 8 and subtract 4 is equivalent to Add 4.

If the first term is 13, the next is 17;

the second term is 21; and

the third term is 25.

What is the velocity of a car that’s traveled 306 kilometers northeast in 3.4 hours

Answers

Answer : -302.6

Step-by-step explanation:

Please help with explanation

1/3 of Cheryl’s savings was the same as 3/4 of Hilda’s savings.Cheryl saved $36.

(a) Find the ratio of Cheryl’s savings to Hilda’s savings.

(b) How much did Hilda save?

Answers

Answer:

a) the ratio is 9:4

b) Hilda did save $16.

Step-by-step explanation:

Let's define the variables:

C = Cheryl's savings.

H = Hilda's savings.

We know that:

(1/3)*C = (3/4)*H

We also know that Cheryl saved $36, then we have:

C = $36

Now we can replace that in the above equation to get:

(1/3)*$36 = (3/4)*H

$12 = (3/4)*H

$12*(4/3) = H = $16

Then Hilda did save $16.

And the ratio between of Cheryl's savings to Hilda's savings is:

36 : 16

We can simplify this if we divide both by 2.

(36/2) : 16/2

18 : 8

Again, we can divide both by 2:

(18/2) : (8/2)

9 : 4

Then the ratio is 9 : 4

A new car is purchased for 20700 dollars. The value of the car depreciates at 11% per year. What will the value of the car be, to the nearest cent, after 11 years?

Answers

Answer:

The answer for that is 5744.61

Find the slope of the line passing through each of the following pairs of points (0,7), (0,-8)

Answers

Answer:

Step-by-step explanation:

Answer:

The answer is unidentified

Step-by-step explanation:

I checked ;)

What is the polar form of -3 + sq rt 3i?

Answers

Answer:

(√12,-π/6)

Step-by-step explanation:

r^2 = 9+3 = 12

tanθ = √3/-3 = -1/√3

Answer:

D

Step-by-step explanation:

Correct on edge



Jollibee employs a total of 10 cashiers and 15 kitchen crews. The manager selects a team of 2 cashiers and

4 kitchen crews for a graveyard shift. In how many ways can the manager select a team?

Answers

Answer:

The manager can select a team in 61425 ways.

Step-by-step explanation:

The order in which the cashiers and the kitchen crews are selected is not important. So we use the combinations formula to solve this question.

Combinations formula:

[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]

In how many ways can the manager select a team?

2 cashiers from a set of 10.

4 kitchen crews from a set of 15. So

[tex]T = C_{10,2}*C_{15,4} = \frac{10!}{2!(10-2)!}*\frac{15!}{4!(15-4)!} = 45*1365 = 61425[/tex]

The manager can select a team in 61425 ways.

PLZ HELP ME YOU GUYS ARE MY ONLY HOPE!!! I WILL GIVE BRAINLIEST PLZ ANSWER<3
2a+3c=5a+2c=1

There is an ordered pair that is the solution of the system of equations shown. The value of one of the variables in the solution of the system can be obtained by using which of the following substitutions?

Answers

Answer:

a = 9, c = -4?

Step-by-step explanation:

i think these are the two equations, let me know if i'm wrong

2a + 3c = 5; a + 2c = 1

rearrange second equation : a = -2c +1

plug in:

2(-2c +1) +3c = 5

-4c +1 +3c = 5

-c +1 = 5

-c = 4

c = -4

a + 2(-4) = 1

a - 8 = 1

a = 9

a=9, c=4 is the answer good luck

0.36 divided by 2.34

Answers

Answer:

0.15384615384

Step-by-step explanation: Often times, this number will be rounded to the nearest hundreth to be .15

Answer:

=0.1538461538461538

Step-by-step explanation:

Hope this helps (:

Solve the right triangle round your answer to the nearest tenth

Answers

Answer/Step-by-step explanation:

✔️A = 180° - (50° + 90°) (sum of triangle)

A = 40°

✔️Find a:

Reference angle = 50°

Opposite = 17

Adjacent = a

Therefore, using trigonometric ratio, we have the following:

Tan 50 = 17/a

a = 17/tan 50

a = 14.3 (nearest tenth)

✔️Find c using Pythagorean Theorem:

c² = a² + b²

c² = 14.3² + 17²

c = √493.49

c = 22.2 (nearest tenth)

Can you guys help me and answer this math question below please I’ll mark brainliest to whoever answers

Answers

the answer to this problem is (2,4)

Answer:

Your answer will be (2,4) :)

Factor to write an equivalent expression for -9x+15y

Answers

Answer:

Step-by-step explanation:

-9x +15y = 3(-3x +5y) = -3(3x - 5y)

The required equivalent expression for the given expression -9x + 15y is 3(-3x + 5y).

What is the Factorization?

Factorization, also known as factoring, is the breakdown of one element into a product of other objects, or factors, which when multiplied together generate the original. For example, the number 21 factors into primes as 3 × 7, and the polynomial x² − 9 factors as (x+3)(x-3).

The given expression is given as follows:

-9x + 15y

It is required to find the factorization of the given expression.

As per the question, we have

-9x + 15y

To factor -9x + 15y, we can first factor out the greatest common factor (GCF) of -9 and 15, which is 3:

-9x + 15y = 3(-3x + 5y)

Therefore, the equivalent expression for -9x + 15y is 3(-3x + 5y).

Learn more about the Factorization here:

brainly.com/question/4184435

#SPJ3

Previous balance: $1,221.35; payment: $300; new purchases: $25.90 and$18.53; periodic rate: 1.75%

Answers

Answer:

1478.67

Step-by-step explanation:

50 points I WILL ALSO MARK BRAINLIEST ITS TIMED PLZ HURRY

The coordinates of the vertices of a polygon are shown on the graph below.

On a coordinate plane, point A is at (negative 4, 3), point C is at (0, negative 3), and point B is at (negative 4, negative 3).
What is the name of the polygon?
octagon
pentagon
quadrilateral
triangle

Answers

Answer:

Triangle

Step-by-step explanation:

In My Knowledge

Option D. triangle

Jolyn was paid $340 last week working 17 hours. What was Jolyn’s hourly pay? Do not include the units in your answer

Answers

Answer:

20

Step-by-step explanation:

It is mentioned that Jolyn made $340 in 17 hours last week. In order to evaluate this, you'll have to divide the money earned by the hours worked.

[tex]\frac{340}{17} =20[/tex]

Therefore, Jolyn makes $20 an hour as 20 x 17 = 340 which is correct,

Hurry pls need answers
10pts

Answers

Answer:

Why is the pic black

Step-by-step explanation:

A restaurant chef made 4 1/2 pints of mushroom soup Each bowl of soup holds 1/2 of pint. How many bowls of soup will.the chef be able to fill?

Answers

Answer:

4 2/4

Step-by-step explanation:

4 1/2 + 1/2 = 4 2/4

i just added em up

Answer:

Step-by-step explanation: 4 1/2 pints / 1/2 pint/ bowl = (9/2) / (1/2) = 9/2 pints x 2 bowl/pint = 18/2 bowls = 9 bowls. QED.

What is the solution of the equation 5* - 1 = 45? Round your answer to the nearest ten-thousandth.

Answers

What does the * mean

Answer:

The answer is 3.3652

Step-by-step explanation:

Find the number in the thousandth place  

5

and look one place to the right for the rounding digit  

2

. Round up if this number is greater than or equal to  

5

and round down if it is less than  

5

.

3.365

Algebra roller coaster building it most state from the ground and it have to be 100ft

Answers

Answer:

sa taas nito ay 50 square meter kung pagbabasihan mo sa ibaba 55 square meter malaki rin sa baba kaya ang tawag dyaan ay centementer

I hope I can help you and give me a star even if I am only 5 or 4 stars and please put a heart for many

Find the diffrence between 7/8 and 1/2 and find the sum of 1/5 and 2/3

Answers

Answer:

3/8 and 13/15

Step-by-step explanation:

find the common denominator

Q3
Work out the volume of each of these items:
a) a bag of sugar of mass 1000 g and density 1.6 g/cm
b) a packet of margarine with density 2.8 g/cm and mass 250 g

Answers

Answer:

Step-by-step explanation:

1000 g × (1 cm³)/(1.6 g) = 1000/1.6 cm³ = 625 cm³

:::::

250 g × (1 cm³)/(2.8 g) = 89.3 cm³

which one is the answer

Answers

Answer:

Two

Step-by-step explanation:

PLS ANSWER IN 5 MINS
I WILL MARK BRAINLIEST
THE QUESTION IS IN THE PICTURE I ATTACHED

Answers

Answer:

[tex]\frac{19}{14}x + \frac{97}{56}[/tex] =

^^^hope this helps! :)

CEOLATIONS AND INEQUALITIES
Finding angle measures of a triangle given angles with variables
In the triangle below, suppose that m U=(x+9)°, m = (2x+1), and mW=(7x)".
Find the degree measure of each angle in the triangle.

Answers

Answer:

seventeen degrees(17⁰)


What decimal does the model represent?
The model below is shaded to represent 2
A 25.6
2.056
2.56
0.256

Answers

Answer:

2.56

Step-by-step explanation:

The answer is 2.56 tyytttttggggg

6. Cindy and Sam are 24 miles apart on a path when they start moving
toward each other. Cindy runs at a constant speed of 10 miles per
hour, and Sam walks at a constant speed of 6 miles per hour.
How long does it take until Cindy and Sam meet?

Answers

Answer:

2 hours to meet each other

Step-by-step explanation:

Answer:

1.5

Step by step explanation:

What is 5/10 = x/100

Answers

Answer:

= 50

Step-by-step explanation:

What the top guy said
Other Questions
You are a droplet of water in the atmosphere over a desert. You fall to the ground. What happens to you next? What pathway do you take? Take me through the water cycle by describing possible scenarios. Be creative! The chemical reaction shown is called photosynthesis. It involves water reacting with carbondioxide to produce glucose (see formulae below) and another gas. The chlorophyll in leavesacts as a catalyst. ON A PIECE OF PAPER. Write a (BN level) word equation. (G Level)Equation with formulae. (P-E) Balanced chemical equation with states.*CoH1206 How would you use a Venn diagram to compare subject and theme?Please dont take my points:/ regular reflection is the reflection of light on a surface What was the Scientific Revolution of the mid-1500s and 1600s? What is the scientific method? List the major steps of the scientific method. What are the lasting consequences of the scientific revolution? Last year, Tim rode his bike a total of 50 3/8 miles. This year, he rode his bike a total of 258 3/4 miles. Which of the following explains about how much farther Tim rode his bike this year than last year? A. About 200 times farther; Subtract last year's distance from this year's distance to get 208 3/8.Then round to the nearest hundred to get 200.B. About 50 times farther; Round each distance to the nearest whole number.Then multiply last year's distance by 50 to see that 259 is close to 50 5.C. About 10 times farther; 258 is about 5 times 50, and 34 is 2 times 38, so multiply 5 2 to get 10. D. About 5 times farther; Round each distance to the nearest whole number.Then multiply last year's distance by 5 to see that 259 is close to 50 5. 7a^3b-7ab^3 needs factoring plz please help! :) ilysm!! Answer for 5 stars answer and a heart with a comment. Please hurry!Here is a diagram of a person standing next to a lorry.The diagram shows two centimetre rulers.The person and the lorry are drawn to the same scale.The lorry is approximately 9.5 m in length.Using the scale diagram, estimate the height of the person in metres. The primary reason for the path of motion of an object being a smooth curve is: Select an answer and submit. For keyboard navigation, use the up/down arrow keys to select an answer. a the third derivative of parabolas is always zero. b inertia. c tangent direction unit vectors change continuously. d calculus must have continuous derivatives to apply correctly. De qu manera las redes sociales estn transformando el mundo?Ayuda ! Help! Which word contains a syllable with a schwa sound? A. caring B. handshake C. compare D. harpoon Ron sells bananas for $0.60 each. How many bananas did Ron sell if he made $150.00, after taking off $39.00 for his banana stand rental? HELP ME PLSSSSSS ASAP can u please help me with this Identify all sets to which the number -7 belongs. every cell in an organism has the same number of chromosomes excepta) skin cellsb) neuronsc) white blood cellsd) reproductive cells how does the monster in wrinkle in time compare and contrast with the monster in monsters or due on maple street The medical practice you are working at has seen an average of 22.4 patients a day for the past 3 months. 3/4ths of those patients have insurance in one form or another. Evaluate 4^0x^-5 when x=2 .