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serious [3.7K]
3 years ago
7

Colbalt-60 has half-life of about 5 years, How many grams of a 300 g sample will remain after 20 years?

Mathematics
2 answers:
ZanzabumX [31]3 years ago
5 0

Answer:

After 20 years 18.75 gm of sample will remain.

Step-by-step explanation:

Rashid [163]3 years ago
4 0

The half-life is the time it takes for any amount of Cobalt-60 to decay to half the starting amount.

20 years is 4 times the half-life of 5 years. So there would be

(300 g) / 2⁴ = 18.75 g

remaining after 20 years.

In other words, after 5 years, 300 g decays to 150 g.

After another 5 years (total 10 years), 150 g decays to 75 g.

After another 5 years (total 15 years), 75 g decays to 37.5 g.

After another 5 years (total 20 years), 37.5 g decays to 18.75 g.

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What is the measure of angle ABC
sertanlavr [38]
3x+25=90
     -25=-25

3x=65
x=26.6666666666666666666666


I hope this helps!
7 0
3 years ago
Average winter temperatures in 45 states were recorded and divided by geographic region. Choose True or False for each statement
san4es73 [151]

Answer: SU, TU, ST is the right answer

Step-by-step explanation: In a triangle

The largest side and the largest angle are opposite to each other

The shortest side and the shortest angle are opposite to each other.

So using the above axioms we can observe the triangle.

The largest angle is m∠U = 80° so the side opposite to it is the largest i.e. ST is the largest

The smallest angle is m∠T = 25° so the shortest side is SU

The third side will be the middle side as the angle ∠S is greater than 25° and less than 80°

So the sides in order from least to greatest are: SU, TU, ST

5 0
3 years ago
Why is the value of q?
Rudiy27

Given:

QSR is a right triangle.

QT = 10

TR = 4

To find:

The value of q.

Solution:

Hypotenuse of QSR = QT + TR

                                 = 10 + 4

                                 = 14

Geometric mean of similar right triangle formula:

$\frac{\text { hypotenuse }}{\text { leg }}=\frac{\text { leg }}{\text { part }}$

$\Rightarrow \frac{14}{q} =\frac{q}{4}

Do cross multiplication.

$\Rightarrow14\times 4 =q\times q

$\Rightarrow 56 =q^2

Switch the sides.

$\Rightarrow q^2 =56

Taking square root on both sides.

\Rightarrow q =2 \sqrt{14}

The value of q is 2 \sqrt{14}.

8 0
3 years ago
The children from a football club are put into rows in the sports hall. When put into rows of 9 children, there are 2 children l
g100num [7]

We are told that the children from a football club are put into rows in the sports hall. When put into rows of 9 children there are 2 children left over. When put into rows of 12 children there are 2 children left over.

We will find least number of children in football club by finding LCM of 9 and 12.

Multiples of 9 are: 9, 18, 27, 36, 45, 54, 63,...

Multiples of 12 are: 12, 24, 36, 48, 60, 72, 84,...

We can see that least common multiple of 9 and 12 is 36.

We are told that 2 children left over from putting them into 9 and 12 children per row. To find least number we will add 2 to 36.

9\cdot4+2=36+2=38

12\cdot3+2=36+2=38      

\text{Least number of children in football club}=36+2=38

Therefore, the least number of children in the football club is 38.

5 0
3 years ago
Maddie is making pineapple punch for her birthday party. The recipe says you need 3 cups of pineapple juice for every 4 cups of
Fed [463]
She will need 12 cups of pineapple juice.
Example: 4 x 4 = 16
3 x 4 = 12
7 0
3 years ago
Read 2 more answers
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