Answer:
x =417.6
Step-by-step explanation:
0.5x+78.2=287
Subtract 78.2 from each side
0.5x+78.2-78.2=287-78.2
.5x =208.8
Divide each side by .5
.5x/.5 = 280.8/.5
x =417.6
Element X is a radioactive isotope such that every 13 years, its mass decreases by half. Given that the initial mass of a sample of Element X is 90 grams, how long would it be until the mass of the sample reached 62 grams, to the nearest tenth of a year?
Answer:
The mass of Element X will reach 62 grams in 7.0 years.
Step-by-step explanation:
We can find the time of decay of Element X by using the exponential decay equation:
[tex] \frac{dm}{dt} = -\lambda t [/tex]
The solution of the above equation is:
[tex]m_{(t)} = m_{0}e^{-\lambda t}[/tex] (1)
Where:
t: is the time =?
λ: is the decay constant
[tex]m_{(t)}[/tex]: is the mass at time t = 62 grams
[tex]m_{0}[/tex]: is the initial mass = 90 grams
First, we need to calculate λ
[tex] \lambda = \frac{ln(2)}{t_{1/2}} [/tex] (2)
Where [tex]t_{1/2}[/tex] is the half-life = 13 years
By entering equation (2) into (1) and solving for "t" we have:
[tex]\frac{m_{(t)}}{m_{0}} = e^{-\frac{ln(2)}{t_{1/2}}*t}[/tex]
[tex]ln(\frac{m_{(t)}}{m_{0}}) = -\frac{ln(2)}{t_{1/2}}*t[/tex]
[tex]t = -ln(\frac{m_{(t)}}{m_{0}})(\frac{t_{1/2}}{ln(2)}) = -ln(\frac{62}{90})(\frac{13}{ln(2)}) = 7.0 y[/tex]
Therefore, the mass of Element X will reach 62 grams in 7.0 years.
I hope it helps you!
41. Steven wants to buy a $535 bicycleSteven has no money saved, but will be able to deposit $30 into a savings account when he receives his paycheck each Friday. However, before Steven can buy the bike, he must give his sister $65 that he owes her. For how many weeks will Steven need to deposit money into his savings account before he can pay back his sister and buy the bike?
Answer:
17 weeks of deposits will pay for his bike and his sister
Step-by-step explanation:
HELP PLEASE
identify the solution to the system of equations
Answer:
solved graphically,
it's just the point where the two lines intersect
Question 9 The spinner pictured is spun 100 times and lands in sector A 40 times. What is the experimental probability of the spinner landing on the sector labeled A? NEED ANSWER ASAP FOR A TEST
someone help please I'm having a hard time understanding
Answer:
the angle shown is a straight angle value of which is equal to 180°
3x + 30. 6 = 180
3x = 180 - 30. 6
3x = 149.4
x = 49.8Find the slope
(-5,2) (-12,-11)
Answer:
m= 13/7
Step-by-step explanation:
(-5, 2) , (-12, -11)
Slope(m)
m= (y2-y1)/(x2-x1)
m= (-11 - 2)/(-12 + 5)
m= (-13)/(-7)
m= 13/7
I need the answer immediately!!!!!!!!
Answer:y=-5x-2
Step-by-step explanation:
This will have a negative slope since the line goes from left to right. Use rise over run to find the slope of -5 and look at the y axis where it intersects to get -2
Have a great day!
Item 4
Find the surface area of the prism.
The surface area is
a
square feet.
Answer:
xnxnxnzznchamschdntjekdfurnthsjdnfjdjdjdkdkr
Step-by-step explanation:
xmxmxnxmxmxnxmxnxndmsndfhakxufmrjdkxddjrf7sjrifxisufkf8dhrkfdkshgshdbfjdddnfjfkdnfmcmcmdmdkfkfkkfdkfkfkfkfkfkfkfkkfkfkfkfkfkdkdkdmdkdkdkdkdmdmrmddmrm1520195126152019512615201951261520195126152019512615201951261520195126152019512615201951261520195126152019512615201951261520195126152019512615201951261520195126152019512615201951261520195126152019512615201951261520195126152019512615201951261520195126152019512615201951261520195126152019512615201951261520195126
Evaluate: 4x(5+3)=8-2
A 2
B 8
C 12
D 15
Answer:
The answer to the problem is 15.
HELPPPPPPPPPPPPPPPPPPPPPPPPP
Answer:
720
Step-by-step explanation:
This is a permutation of 10 choose 3
10 ! 10!
----- = ------------ = 10*9*8 = 720
(10-3)! 7!
The young mathematician is presented with this problem: (13 + 7) x (5 - 3) / 4 x (1 + 1) = Which operation would the young mathematician do first?
The division
The subtraction
Those inside parentheses
The multiplication
Those inside the parentheses. Rember pemdas or Parentheses Exponets Multiple Divide Add Subtract in that order from left to right
KLM is isosceles. Calculate the segment EF from the data in the drawing.
HELP!!
Answer:
4.5 cm
Step-by-step explanation:
KL = LM as triangle is isosceles
LM = KM as LF = FM = KN = NM, so the triangle is equilateral
EF ║ NM as LE⊥EF and LN⊥NM
EF is half the midsegment as ∠KLN ≅ ∠MLN, and LN is angle bisector of ∠KLM
Midsegment is half the side length, and all sides are 18 cm.
EF = 1/2(1/2*18) = 4.5 cm
please help!!!!!! i will mark brainliest!
Answer:
d
Step-by-step explanation:
Answer PLSSS..................
rectangle = 3 x 2 = 6 cm2
cirrel = pier2 = 3.14 x 7 x 7 = 3.14 x 49 = 153.86 cm2
153.86 - 6 = 147.86cm2
Points A, B, C, and D are the vertices of a square. Points E and F are the center of two congruent semicircles that are tangent to each other at point G. Which value is closest to the area of the shaded regions?
Answer:
8 sq units
Step-by-step explanation:
to find the area of shaded region:
area of square minus sum of areas of each semi-circle
A(square) = 6² = 36
A (semi-circle) = πr²/2
= π3²/2
= 4.5π
Since there are two semi-circles, that makes one complete circle with an area of 9π
A(circle) ≈ 28 sq units
36-28 = 8 sq units
Tiffany withdrew $20 on fourteen different occasions from her bank account. After the fourteen transactions, what integer represents the change to her bank account balance?
Answer:
$-280
Step-by-step explanation:
Tiffany withdrew $20, 14 times. a withdrawal means the amount in her account would reduce.
total change in balance = 20 x 14 = 280
because it is a withdrawal, a negative sign would be attached
Answer: -280
Step-by-step explanation:
An amount of $45,000 is borrowed for 13 years at 6.75% interest, compounded annually. If the loan
paid back
Use the calculator provided and round your answer to the nearest dollar,
Answer:
$104850
Step-by-step explanation:
Given data
Principal= $45,000
Time = 13 years
Rate= 6.75%
the compound interest expression is
A= P(1+r)^t
A=45000(1+0.0675)^13
A= 45000(1.0675)^13
A= 45000*2.33
A= $104850
Hence the final amount will be $104850
Look at the two 2s in this number
Answer: What number?
Step-by-step explanation:
Answer:
In what number... is this a trick question or did you just not finish your question??
Step-by-step explanation:
China consumes 4 x 10^9 tons of coal, while japan about 2 x 10^8 tons of coal. Approximately how many times the amount of that japan consumed did china consumed
Answer:
20 times
Step-by-step explanation:
This is calculated as:
The number of coal China consumes ÷ The number of coal Japan consumes
The number of coal China consumes =4 × 10⁹
The number of coal Japan consumes
= 2 × 10⁸
4 × 10⁹/2 × 10⁸
= 20 times
∠A and ∠ B ∠B are complementary angles. If m ∠ A = ( 3 x + 25 ) ∘ ∠A=(3x+25) ∘ and m ∠ B = ( 5 x − 7 ) ∘ ∠B=(5x−7) ∘ , then find the measure of ∠ A ∠A.
Answer:
52º
Step-by-step explanation:
Complementary angles are a set of angles that add up to 90º. Knowing this, we can find the value of x by setting the sum of these two angles equal to 90. For example:
3x + 25 + 5x - 7 = 90
8x + 18 = 90
8x = 72
x = 9
Now that we know our x value, we can find the measure of angle A. Simply plug in the value of x to the measurement of angle A, which is 3x + 25.
3(9) + 25 = 52º
What is 4³ written in expanded form?
Answer:
4³=4*4*4 is a required expanded form.
A designer builds a model of a sports car. The finished model is exactly the same shape as the original, but smaller. The scale factor is 2:15
Answer:
[tex]Ratio = 2 : 15[/tex]
Step-by-step explanation:
Given
[tex]k = 2 : 15[/tex] --- scale factor
Required [missing from the question]:
The ratio of width of the model to the original
From the question, we understand that the scale factor is: 2 : 15
The ratio of the width of the model to the original equals the given scale factor i.e.
[tex]Ratio = 2 : 15[/tex]
Expand the logarithm. Assume all expressions exist and are well-defined.
Write your answer as a sum or difference of common logarithms or multiples of common
logarithms. The inside of each logarithm must be a distinct constant or variable.
log 3y
Answer:
Step-by-step explanation:
log 3y = log(y)^3 (exponent)
or
= log(y)*log(y)*log(y) (multiples)
The logarithmic expression y = log(3y) can be written as sum or difference of common logarithms as log(3y) = log(3) + log(y).
What is logarithm? What is a mathematical function, equation and expression?logarithmic : It is a quantity representing the power to which a fixed number (the base) must be raised to produce a given number. Mathematically -[tex]$\log_{b}({b^x})=x[/tex] {where [b] is logarithmic base}
function : In mathematics, a function from a set X to a set Y assigns to each element of X exactly one element of Y. The set X is called the domain of the function and the set Y is called the codomain of the function.expression : A mathematical expression is made up of terms (constants and variables) separated by mathematical operators.equation : A mathematical equation is used to equate two expressions.Given is the following logarithmic expression as -
y = log(3y)
We have the following logarithmic expression -
y = log(3y)
Using the identity of logarithm -
log(AB) = log(A) + log(B)
log(3y) = log(3) + log(y)
Therefore, the logarithmic expression y = log(3y) can be written as sum or difference of common logarithms as log(3y) = log(3) + log(y).
To solve more questions on functions, expressions and polynomials, visit the link below -
brainly.com/question/17421223
#SPJ2
There are 2 quarters, 1 nickel, and 2 dimes in a pocket.
What is the probability of choosing a coin, not returning it to the pocket, and then choosing another of greater value?
A ^3 10
B ^6 25
C ^4 10
D ^8 25
Answer:
C
Step-by-step explanation:
In right triangle ABC, a = 7, b = 9 and
Answer: the answer is 63,ABC
Step-by-step explanation:
Pls help no links pls this is due and i need help
Answer:
angle 1=127 degree
angle 3=127 degree
angle 2=53 degree
angle 4=53 degree
angle 5=37 degree
angle 6=90 degree
angle 7=53 degree
angle 8=37 degree
angle 9=37 degree
angle 10=143 degree
angle 11=37 degree
angle 12=143 degree
Step-by-step explanation:
ITEMS
The calculator shown costs $160.00 after a discount of $40.00 was given
Calculate the cost of the calculator before the discount
Answer:
mp=160
dis=40
now,
sp=mp-dis
=Rs. 160-Rs.40
=Rs. 120
(7.5)What is the value of x?
X
オー2
x + 5
x + ]
A
7.5
B.
10
C
2.5
D
5
Answer:
D 5
Step-by-step explanation:
the same scaling factor s applies to all sides when transforming from the small to the large triangle.
x×s = x + 5
(x-2)×s = x +1
=> s = (x+5)/x
=> (x-2)×(x+5)/x = x + 1
=> x² + 3x - 10 = x² + x
=> 3x - 10 = x
=> 2x = 10
=> x = 5
WILL GIVE BRAILIEST!!!
Answer:
Step-by-step explanation:
6^4*612/6^7
6^4*6^12-7
6^4*6^5
6^4+5
6^9
[tex]20\% of gh 200 [/tex]
Answer:
answer
I think it's 40...
[tex]20\% \: \bold{of} \: 200 \\ \\ = \frac{20}{100} \times 200 \\ \\ = \frac{20}{ \cancel{100}} \times \cancel{200} \\ \\ = 20 \times 2 \\ \\ = 40[/tex]
Hope This Helps You ❤️