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wel
2 years ago
9

PLS HELP ME IT IS SO HARD

Mathematics
1 answer:
fiasKO [112]2 years ago
7 0

Answer:

180-28.4 DIVIDED BY TWO SHOULD BE THE ANSWER SO C

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Suppose after 2500 years an initial amount of 1000 grams of a radioactive substance has decayed to 75 grams. What is the half-li
krok68 [10]

Answer:

The correct answer is:

Between 600 and 700 years (B)

Step-by-step explanation:

At a constant decay rate, the half-life of a radioactive substance is the time taken for the substance to decay to half of its original mass. The formula for radioactive exponential decay is given by:

A(t) = A_0 e^{(kt)}\\where:\\A(t) = Amount\ left\ at\ time\ (t) = 75\ grams\\A_0 = initial\ amount = 1000\ grams\\k = decay\ constant\\t = time\ of\ decay = 2500\ years

First, let us calculate the decay constant (k)

75 = 1000 e^{(k2500)}\\dividing\ both\ sides\ by\ 1000\\0.075 = e^{(2500k)}\\taking\ natural\ logarithm\ of\ both\ sides\\In 0.075 = In (e^{2500k})\\In 0.075 = 2500k\\k = \frac{In0.075}{2500}\\ k = \frac{-2.5903}{2500} \\k = - 0.001036

Next, let us calculate the half-life as follows:

\frac{1}{2} A_0 = A_0 e^{(-0.001036t)}\\Dividing\ both\ sides\ by\ A_0\\ \frac{1}{2} = e^{-0.001036t}\\taking\ natural\ logarithm\ of\ both\ sides\\In(0.5) = In (e^{-0.001036t})\\-0.6931 = -0.001036t\\t = \frac{-0.6931}{-0.001036} \\t = 669.02 years\\\therefore t\frac{1}{2}  \approx 669\ years

Therefore the half-life is between 600 and 700 years

5 0
3 years ago
Put them in order from least to greatest:<br> 6.539 6.56 6.4 6.45 6.557 6.481
allsm [11]

6.557,6.539,6.481,6.56,6.45,6.4

7 0
2 years ago
Read 2 more answers
What does x equal in 3x 81 = -9?
vfiekz [6]
Well first of what sign is in between the 3x and 81 
6 0
3 years ago
If p, q and r were three statements such that p → q and q → r then p → r, this is called
jarptica [38.1K]

Answer:  Law of syllogism

Step-by-step explanation:

Law of Syllogism is described as

  • a logical reasoning by using  transitivity.
  • a valid argument that applies deductive reasoning to get the final statement.
  • it is similar to transitive property that if a=b and b=c then a=c.

So if p, q and r were three statements such that p → q and q → r then p → r, this is called <u>law of syllogism</u>.

For example: When Rita gets internet Shamy gets internet. When Shamy gets internet Raj gets internet.

By law of syllogism : When Rita gets internet Raj gets internet.

8 0
3 years ago
What is one third plus one fourth equal to a mixed number
Vikentia [17]
1/3 ⇒ 4/12
1/4 ⇒ 3/12
3/12 + 4/12 = 7/12

You cannot put this as a mixed number
5 0
3 years ago
Read 2 more answers
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