Hello Brainly user :)
If the ratio of olives to croutons is 5:3 and there are 12 croutons, there will be 20 olives
Here is how we know
5(olives) : 3 (croutons)
X (olives) : 12 (croutons)
So if we pay attention, we see that 12 is a multiple of 3. When we divide 12 by 3, we get 4
Knowing that the olives will have the same solution, multiplying 5 and 4 gets us 20, our answer
Hope this helps :)
~Celia