The sum of the digits of a two-digit number is 5. If nine is subtracted from the number, the digits will be reversed. Find the n
1 answer:
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Answer:
<u>Remove "x" and add</u>
-2 + 9 = 7
<u>Add "x" back</u>
7 -----> 7x
Note: When adding/subtracting problems like these remove "x" and then add/subtract normaly. When you get your answer put x back.
Answer:
The equivalent expression for the given expression is
Step-by-step explanation:
Given:
Solution:
We will see first what is Cube rooting.
Law of Indices
Now, applying above property we get
∴ The equivalent expression for the given expression is
If the radio active isotope has the half life of 24100 years, then the initial quantity is 2.16 grams
The half life in years = 24100
Consider the quantity of the radio active isotope remaining
y =
When t = 1000 the y = 1.2
y = C/2 when t = 1599
Substitute the values in the equation
C/2 =
Cancel the C in both side
1/2 =
Here we have to apply ln to eliminate the e terms
ln (1/2) = 24100k
k = ln(1/2) / 24100
k = -2.87× 10^-5
To find the initial value we have to substitute the value of k and y in the equation
1.2 = Ce^{1000 × -2.87× 10^-5}
C = 1.2 / e^(-0.0287)
C = 2.16 gram
Hence, the initial quantity of the radioactive isotope is 2.16 gram
Learn more about half life here
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