First of all, we need to understand that she lost 18 marbles there for she will share 72 - 18 marbles with her friends. Therefore she will share 54 marbles between her and her friends. Now in order to find out the number of marbles each kid gets, we just have to divide 54 by the number of kids (including Eliza). So since there are 9 kids in total, the answer will be...
54 / 9 = 6
Therefore Eliza and each of her friends will get 6 marbles.
