The question is incomplete, here is the complete question:
The half-life of a certain radioactive substance is 46 days. There are 12.6 g present initially.
When will there be less than 1 g remaining?
Answer: The time required for a radioactive substance to remain less than 1 gram is 168.27 days.
Step-by-step explanation:
All radioactive decay processes follow first order reaction.
To calculate the rate constant by given half life of the reaction, we use the equation:
[tex]k=\frac{0.693}{t_{1/2}}[/tex]
where,
[tex]t_{1/2}[/tex] = half life period of the reaction = 46 days
k = rate constant = ?
Putting values in above equation, we get:
[tex]k=\frac{0.693}{46days}\\\\k=0.01506days^{-1}[/tex]
The formula used to calculate the time period for a first order reaction follows:
[tex]t=\frac{2.303}{k}\log \frac{a}{(a-x)}[/tex]
where,
k = rate constant = [tex]0.01506days^{-1}[/tex]
t = time period = ? days
a = initial concentration of the reactant = 12.6 g
a - x = concentration of reactant left after time 't' = 1 g
Putting values in above equation, we get:
[tex]t=\frac{2.303}{0.01506days^{-1}}\log \frac{12.6g}{1g}\\\\t=168.27days[/tex]
Hence, the time required for a radioactive substance to remain less than 1 gram is 168.27 days.
What value of x makes the equation true 7+2x=4x-5
Answer:
6
Step-by-step explanation:
Fact
Answer:
x=6
Step-by-step explanation:
1. 7+2x=4x-5
2. 7+2x-2x=4x-5-2x
7=2x-5
12=2x
x=12/2
x=6
expend log10 (x³y⁵)
Answer:
3log(x) + 5log(y)
Step-by-step explanation:
[tex] log({x}^{3} {y}^{5} ) \\ = log( {x}^{3} ) + log( {y}^{5} ) \\ = 3 log(x) + 5 log(y) [/tex]
There are 1250 students at Cypress Middle School. 42% of the students are enrolled in PE. How many students are enrolled in PE?
Answer:
The answer is 525 students.
Step-by-step explanation:
1250 total students
42% = PE
42% of 1250 = [tex]525[/tex]
Thus, the answer is 525.
Answer: 525 students are enrolled in PE.
Step-by-step explanation:
Write an equivalent expression
8x - 6x + 10y + 6 + 4y + 9 = ?x + ?y + ?
Answer: 2x + 14y + 15
Step-by-step explanation:
8x - 6x + 10y + 6 + 4y + 9
Bring like terms together
8x - 6x + 10y + 4y + 6 + 9
Combine like terms
2x + 14y + 15
Hope this helped!
35 percent as a decimal
Write the negation of the proposition.
Some people don't like walking.
Answer: All people do like walking
It might be more grammatically correct to say "all people like walking", but I wanted to include the "do" in there because we can see how the "don't" flips to "do". The "some" flips to "all" as well.
The negation of a statement is the complete opposite in every way. If a friend makes a claim that some people don't like walking, and you can prove that all people do like walking, then this contradicts your friend. The same can be said in reverse: if your friend claims "all people do like walking", then you can counter back with "some people don't like walking". All it takes is one counter-example to prove the claim "some people don't like walking" to be correct. In terms of logic, the word "some" means "one or more".
What is the probability of rolling a multiple of 3 on a 6-sided die?
Answer:
33% or 1/3 ...............
simplify the expression-14-(-8)
Answer:
the answer is -6
Step-by-step explanation:
-14-(-8)=-6.
Answer:
[tex] - 14 - ( - 8) \\ \\ - 14 +8 \\ \\ = - 6[/tex]
To decorate her bedroom, Lisa spent $62.89 on new bedding, $48.26 on paint, and $81.99 on accessories. About how much did she spend to decorate her bedroom? (1 point)
Question 3 options:
1)
$190
2)
$210
3)
$230
4)
$300
Answer:
3 because it makes a of sense
Step-by-step explanation:
hi help me who is genius this question what are acc that should be Cr and Dr and how will the ledger will be done also a little help will be helpfull
Which order pairs are solution to the inequality Y-3x<-8
Answer:
your answer are c and d hope it helps .
What would this be?!?
Answer:
It's C
3 and 3/4
Step-by-step explanation:
1 dozen=12
2 dozens=24
1 1/2 divided by 24 = 1/16
1/16 times 60
3 and 3/4
helpppp nowww plsss!!
Answer:
6/10
Step-by-step explanation:
6/10
Which statements are true? Check all that apply.
On a coordinate plane, point A is (2, 3), point B is (3, 2), point C is (negative 2, 2), point D is (negative 3, negative 3), point E is (0, 3), point F is (2, 0), and point G is (0, 0).
A is in Quadrant I.
B is on the x-axis.
C is in Quadrant I.
D is in Quadrant III.
E is on the x-axis.
F is on the x-axis.
G is on the y-axis. Please anwser quick!!!!
Given:
A(2, 3)B(3, 2)C(-2, 2)D(-3, -3)E(0, 3)F(2, 0)G(0, 0)Let's first understand the different signs and different quadrants.
Quadrant I: (+, +)Quadrant ll: (-, +)Quadrant III: (-, -)Quadrant IIII: (+, -)Verifying them with the given points,
A is in Quadrant I. - TRUEB is on the x-axis. - FALSEC is in Quadrant I. - FALSED is in Quadrant III. - TRUEE is on the x-axis. - FALSEF is on the x-axis. - TRUEG is on the y-axis. - FALSEHope it helps. :)
Answer:
A D F
Step-by-step explanation:
All credit to him
Choose the equation and the inequality needed to answer this question. Trevor tutors French for $15 and hour and scoops ice cream for $10 an hour. He is going to work 15 hours this week. At least how many hours does he need to tutor to make more than $180? Let x equal the number of hours he tutors and y be the number of hours he scoops ice cream.
Answer:
One second let me look it up for u :)
Step-by-step explanation:
Answer:
Total number of hours = 15
Let the hours spent tutoring french be x.
Therefore hours spent on scooping ice cream = (15 - x)
Amount: Tutoring french is $15 an hour, total for x hours = 15x
For scooping ice cream it is $10 an hour 10*(15 - x) = 150 - 10x
To make more than $180
15x + (150 - 10x) > 180
15x + 150 - 10x > 180
15x - 10x > 180 - 150
5x > 30
x > 30/5
x > 6
trevor needs to tutor 6 hours to make more than 180
Step-by-step explanation:
I hope this helped :)
Which decimal is less than 0.47
(0.38) (0.9) (0.64) (0.5)
Answer:
0.5
Step-by-step explanation:
just divide in a calculator
Answer:
0.38
Step-by-step explanation:
Look at the tenths decimal place to compare
3 is less than 4
9 is greater than 4
6 is greater than 4
5 is greater than 4
The only one less than 4 is 3 which corresponds to the decimal 0.38
What is the measure of x
Answer:
x = 75°
Step-by-step explanation:
From the figure it appears that:
[tex] m\angle B = 36\degree [/tex]
and
[tex] m\angle D = 39\degree [/tex]
x is the measure of the exterior angle of [tex] \triangle BDH[/tex]
Therefore, by exterior angle theorem:
[tex] x = m\angle B+ m\angle D [/tex]
[tex] x = 36\degree+ 39\degree [/tex]
[tex] x =75\degree [/tex]
Please solve the question below
Answer:
AB = 14 units
∠F = 39°
Step-by-step explanation:
Given:
ΔABC ≅ ΔDEF
So,
AB = ED (By CPCT)
So,
AB = 14 units
∠C = ∠F (By CPCT)
∠F = 39°
Use the ALEKS calculator to find 62% of 80. Do not round your answer.
Answer:
ok Naruto
Step-by-step explanation:
49.6
The large rectangle below represents one whole.
What percent is represented by the shaded area?
%
2x2+3x-14=0 Does anyone know the answer?
Answer:
Answers l thenk (1.16)
Mmmmm
Evaluate the following: (½)(10) −(−12) −25
Answer:
-8
Step-by-step explanation:
1/2 times 10 is 5. and a negative times a negative is a positive, so you have a positive 12, which becomes 5+12-25, which is -8
Jose has $20 and is saving $6 per week. Ana has $150 and is spending $4 per
week. When will they both have the same amount of money?
What is the coefficient in -x^2?
Answer:
-x i belive it might just be x tho
Step-by-step explanation:
Use this table to match the molecules with their estimated masses.
Atom Mass (in grams)
hydrogen 1.67 × 10-24
oxygen 2.66 × 10-23
carbon 1.99 × 10-23
nitrogen 2.32 × 10-23
Answer:
7.31 x 10^-23
Answer: CO2 (1 atom of carbon and 2 atoms of oxygen)
3.34 x 10^-24
Answer: H2 (2 atoms of hydrogen)
2.821 x 10^-23
Answer: NH3 (1 atom of nitrogen and 3 atoms of hydrogen)
7.64 x 10^-23
Answer: NO2 (1 atom of nitrogen and 2 atoms of oxygen)
Step-by-step explanation:
hope this helps :)
7.31 x 10^-23 = CO2 i.e. 1 atom of carbon and 2 atoms of oxygen
3.34 x 10^-24 = H2 (2 atoms of hydrogen)
2.821 x 10^-23 = NH3 (1 atom of nitrogen and 3 atoms of hydrogen)
7.64 x 10^-23 = NO2 (1 atom of nitrogen and 2 atoms of oxygen)
Learn more: https://brainly.com/question/4804019?referrer=searchResults
A store is having a special on candy bars. The special is 4 boxes of candy bars for $11.00. Which statement about the box of candy bars is true?
Answer:
answer is c (2.75)
Step-by-step explanation:
Jordyn's rectangular garden is represented in the diagram below. If a diagonal walkway crosses their garden, what is its length, in feet?
Walkway
8 feet
15 feet
Answer: 23
Step-by-step explanation:
Philip George and matt are water polo players. The diagram below represents the players positions during a game
What is the measure of the angle at George’s position
A. 6°
B. 37°
C. 60°
D. 83°
Answer:
It 6
Step-by-step explanation:
Answer:
83 degrees
Step-by-step explanation:
10x+23+8x+12+55-3x=180
15x=90
x=6
10(x)+23 is George's position angle
10(6)+23 =83 degrees
In ANOP, NP is extended through point P to point Q,
mZOPQ = (6x – 15)°, mZPNO = (2x + 18)°, and
mZNOP = (2x – 13). What is the value of x?
Answer:
x = 10
Step-by-step explanation:
Form the information given, we can deduce that:
m<OPQ is an exterior angle of ∆NOP = (6x - 15)°
m<PNO = (2x + 18)° and m<NOP = (2x - 13)° are both interior angles that are opposite to the exterior angle.
Therefore, based on the exterior angle theorem:
m<OPQ = m<PNO + m<NOP
(6x - 15)° = (2x + 18)° + (2x - 13)°
Solve for x
6x - 15 = 2x + 18 + 2x - 13
6x - 15 = 4x + 5
6x - 15 - 4x = 4x + 5 - 4x (Subtraction property of equality)
2x - 15 = 5
2x - 15 + 15 = 5 + 15 (addition property of equality)
2x = 20
2x/2 = 20/2 (division property of equality)
x = 10
In a hotel, Elevator 1 stops at the third floor at an elevation of 40ft. Elevator 2 stops at the parking level at an elevation of -25ft.
How far apart, in feet, are the two elevators? Show or explain your work.
PLEASEEE ANSWER!!!
Answer:
65 ft
Step-by-step explanation:
Negative and positive numbers can be expressed as how far away they are from zero.
40 is 40 units away from zero. Elevator 1 is 40 units from 0.
-25 is 25 units away from zero. Elevator 2 is 25 units from 0.
To find the distance, we'll add their distances from 0.
40 + 25 = 65
They are 65 units apart. In your problem you specify feet, so they are 50 ft apart.