Solution

36387

First name
Sally and Stephanie
School
Greenacre Public School
Country
Age
11

Solution:

Envelope 3: card 0/3

Envelope 7: card 2/5

Envelope 13: card 4/9

Envelope 14: card 6/8

If these numbers are all correct, then envelope 8 has to have the cards 1 and 7.