The older one about eight, the little one about four. The older girl put the money on the counter and told the lady who served them what flavor they wanted. The first cup was soon done and the lady told her

"Here's the first one, why don't you give it to your little sister?"

The older girl said
"She will wait for the second cup!"

and started licking on hers. The lady said to the little girl

"Oh, I just see that you are lucky today - there's more than one portion in the box but not enough for a full size to sell - so you get some more ice cream for no extra charge!"

The moment she put it on the counter the older girl hastily grabbed it , handed the already half eaten cup to the little sister and said

"I'll take the big one so you don't get sick from too much ice cream and you can have the other one!"

[We have a saying for this in German, hard to translate exactly, but similar to the following:
"Brotherly divided - Sisterly cheated"]