Question

I need help understanding a question!



A box has12 books and is 1/3 full.

How many books will be in the box when it's full?

The answer is 36, but Idk how they got it, thanks.

Answer 1

You could set up a ratio:

12 books (1/3) box
---------- = ---------
x books 1 box

Try cross multiplication. Solve for x.

Answer 2

12 times 3=36 so 36 is your answer

Answer 3

obviously, but why 3?

Answer 4

1/3 the denominator is 3

Answer 5

so multiply 3

Answer 6

cross multiply the following:

12 books (1/3) box
---------- = ---------
x 1 box

Then solve the resulting equation for x.

Answer 7

ok, thanks. How do I remove a fraction from an equation? Do I multiply something by the numerator?

Answer 8

Look what you get by cross multiplication:

(12 books)(1 box) = (x)( [1/3] box)

You want to remove that fraction? Fine. Multiply both sides of this equation by 3.