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Savatey [412]
3 years ago
11

The decay rate for a radioactive isotope is 9.29.2 percent per year. find the half-life of the isotope. round to the nearest ten

th of a year.
Mathematics
1 answer:
Oxana [17]3 years ago
4 0
Exponential decay is given by the equation

F = P(1 - r)^t

0.5 = 1(1 - 0.092)^t

0.5 = (0.908)^t

log 0.5 = log (0.908)^t

log 0.5 = t * log 0.908

t = (log 0.5)/(log 0.908)

t = 7.18

Answer: 7.2 years
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After 3 hours of of driving, Paul had gone 183 miles. What was his average rate of speed? Explain your answer.
snow_lady [41]

Answer:

The average rate of speed is 61!

Step-by-step explanation:

183 miles divided by 3 hours of driving is 61 average rate of speed. :)

6 0
3 years ago
Read 2 more answers
If a=i+7j+k and b=i+11j+k, find a unit vector with positive first coordinate orthogonal to both a and
Scilla [17]
Take the cross product, then normalize the result.

\mathbf a\times\mathbf b=\begin{vmatrix}\mathbf i&\mathbf j&\mathbf k\\1&7&1\\1&11&1\end{vmatrix}=-4\,\mathbf i+4\,\mathbf k

This has norm

\|\mathbf a\times\mathbf b\|=\sqrt{(-4)^2+4^2}=4\sqrt2

and so a unit vector orthogonal to both given vectors is

\dfrac{\mathbf a\times\mathbf b}{\|\mathbf a\times\mathbf b\|}=-\dfrac1{\sqrt2}\,\mathbf i+\dfrac1{\sqrt2}\,\mathbf k

An equally correct answer would be the negative of this vector, since \mathbf b\times\mathbf a=-\mathbf a\times\mathbf b.
5 0
3 years ago
HELP Please<br>I really need the answer​
SpyIntel [72]

Step-by-step explanation:

a full circle has 360°.

so, since each individual result is represented by an amount of degrees, the total sum of all results must be 360°.

labour = 360 - 136 - 34 - 54 - 14 = 122°

the fraction 122/360 represents the 183 votes for labour.

122/360 = 183

the fraction 1/1 = 1 then represents the total number of votes in the whole system.

61/180 = 183

1/180 = 3

1 = 3×180 = 540

540 pupils voted altogether.

3 0
2 years ago
Answer quickly, please. I need this. I will give brainliest to whoever answers first. You also get 25 points for this
sukhopar [10]
** DISCLAMIER** am not completely sure. Please do not use my answer unless you are very desperate.

since O,R correspond with A,N I think you half F on each side and add it to 11.2 so
10 divided by 2 = 5
7 is already half.
5 + 7 is 12
12 + 11.2 = 23.2

IF THIS IS WRONG TRY 17
reason for 17:
10 + 7 = 17
If you look at both lines they look the same length as A, N.
3 0
3 years ago
Cody wants to watch a movie that is 3 hours long he has watched 1/6 of the movie. How much time did Cody spend watching the movi
Anettt [7]

Answer:

3 hours is 60×3=180

1/6 of 180 =180÷ 6= 30

30 mins is the answer

Step-by-step explanation:

if you want to find another position other than 1/6 like 4/6 then you can just times the answer in this case 30 by the amout u need in this case 4 so 4/6 would be 120 which is 2 hours

8 0
3 years ago
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