There are 12 paperback mysteries on a shelf. This is 40% of the books on the shelf.
How many total books are on the shelf?
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There are 30 books in the shelf.

Step-by-step explanation:

To solve this problem we can use a rule of three in such a way that 12 paperback mysteries are related to 40% of the books in the shelf in the same proportion that "x" total books are related to 100% of the books in the shelf. So we have:

12 -> 40%

x -> 100%

40*x = 12*100

40*x = 1200

x = 1200/40

x = 30 books

There are 30 books in the shelf.

There are 30 books on the shelf.

Step-by-step explanation:

12 paperback mysteries are on the shelf. And this is 40% of the books on the shelf.

Let the number of books on the shelf be represented by x. So that:

        40% of x = 12

        × x = 12

         =  12

Multiply both sides by 100, to have;

     40x = 1200

Divide through by 40,

     x =

     x = 30

The number of books on the shelf is 30.

the answer is: d) o, f, and kr.

atomic radius of bromine (br) is 114 pm.

atomic radius of oxygen (o) is 73 pm.

atomic radius of fluorine (f) is 72 pm.

atomic radius of krypron (kr) is 112 pm.

the atomic radius of a chemical element is a measure of the size of its atom.

the atomic radius varies with increasing atomic number, but usually increases because of increasing of number of electrons.

the atomic radius decreases across the periods because an increasing number of protons, because greater attraction between the protons and electrons.

asdsad

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