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Anni [7]
3 years ago
10

Element X is a radioactive isotope such that every 21 years, its mass decreases by half. Given that the initial mass of a sample

of Element X is 40 grams , how much of the element would remain after 9 years , to the nearest whole number?
Mathematics
1 answer:
Darina [25.2K]3 years ago
4 0

Answer:

30 grams

Step-by-step explanation:

Use the half life equation:

A = P (½)^(t / T)

where P is the initial amount, t is time, and T is the half life length.

Given P = 40, t = 9, and T = 21:

A = 40 (½)^(9 / 21)

A ≈ 30

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Please help and thank you
Gekata [30.6K]

Answer:

A. 11\frac{5}{8}\textrm{ inches}

Step-by-step explanation:

Given:

The regular polygon is a decagon having 10 sides.

Perimeter of the given polygon is,

P=116\frac{1}{4}\textrm{ inches}=116.25\textrm{ inches}.

We know that, perimeter of a regular polygon of n sides is given as,

P=na where, a is the length of each side.

Here, n=10,P=116\frac{1}{4}\textrm{ in}

Plug in these values and solve for a. This gives,

P=na\\116\frac{1}{4}=10a\\116.25=10a\\a=\frac{116.25}{10}=11.625=11+\frac{625}{1000}=11+\frac{5}{8}=11\frac{5}{8}\textrm{ in}

Therefore, the side length of the given polygon is 11\frac{5}{8}\textrm{ inches}

3 0
2 years ago
A solid has faces that consist of two squares and four congruent rectangles. What type of solid is it?
lozanna [386]
<span>A solid that has faces which consist of two squares and four congruent rectangles is called a rectangular prism. It </span><span>has six faces that are rectangles. It has the same cross-section along a length, which makes it a </span>prism<span>. It is also a "cuboid". Hope this answers the question.</span>
3 0
3 years ago
Read 2 more answers
Evaluate a^2b^2? when a = 5 and b = 3.
kvasek [131]

Answer:

D) 7

Step-by-step explanation:

a^{2} -2b^{2}

a=5

b=3

\left(5\right)^2-2\left(3\right)^2

Calculate 5 to the power of 2 and get 25:-

25-2\times 3^{2}

Calculate 3 to the power of 2 to get 9 and then multiply 2 and 9 to get 18:-

25-18

=7

<u>OAmalOHopeO</u>

5 0
2 years ago
Todo numero es divisible por 3, si al sumar el total de sus digitos, se obtiene un numero mutiplo del tres (se puede expresar co
Free_Kalibri [48]

Answer:

si, eso es correcto

Step-by-step explanation:

Espero que esto ayude a marcar el MÁS CEREBRAL !!!

7 0
3 years ago
Solve f(-7) for f(x) = 17 – X
grigory [225]

Answer:

f(-7) = 24

Step-by-step explanation:

Step 1:  Identify the Function

f(x) = 17 - x is the function

Step 2:  Set x to -7 in the function

f(-7) = 17 - (-7)

f(-7) = 17 + 7

f(-7) = 24

Answer: f(-7) = 24

8 0
3 years ago
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