108 identical books have a mass of 30kg what's the number of such books that have a mass of 20 kg
Need help!
one book mass = 30 / 108
so (30/108) n = 20
n = 20 *108 /30
= (2/3)(108) = 2*36 = 72 books
2/3 the mass, so 2/3 the books: 2/3 * 108 = 72
or, as a proportion,
x/20 = 108/30
x = 72
Sure! To find the number of books that have a mass of 20 kg, we can set up a proportion using the information given.
Let's call the unknown number of books we're trying to find "x."
The mass of the 108 identical books is 30 kg. Therefore, we can set up the following proportion:
108 books / 30 kg = x books / 20 kg
To solve this proportion, we can cross-multiply:
108 books * 20 kg = x books * 30 kg
2,160 kg = 30x kg
Now, we can solve for x by dividing both sides of the equation by 30:
2,160 kg / 30 kg = x
x ≈ 72
Therefore, there are approximately 72 books that have a mass of 20 kg.