Step-by-step explanation:

The answer is quite straightforward...
That's $56 per 80 grams.
($56)/(80g)
Explanation:
Rather than trying to guess and check, we can actually construct a counterexample to the statement.
So, what is an irrational number? The prefix "ir" means not, so we can say that an irrational number is something that's not a rational number, right? Since we know a rational number is a ratio between two integers, we can conclude an irrational number is a number that's not a ratio of two integers. So, an easy way to show that not all square roots are irrational would be to square a rational number then take the square root of it. Let's use three halves for our example:

So clearly 9/4 is a counterexample to the statement. We can also say something stronger: All squared rational numbers are not irrational number when rooted. How would we prove this? Well, let
be a rational number. That would mean,
, would be a/b squared. Taking the square root of it yields:

So our stronger statement is proven, and we know that the original claim is decisively false.
Gianna paid less per necklace so she got the better deal
Gianna: 50.75 / 7 = 7.25
So she paid $7.25 per necklace
Winnie: 24.60 / 3 = 8.20
So she paid $8.20 per necklace