Solution

39195

First name
Hams ah and Saira
School
Edith Neville Primary School
Country
Age
9

First of all I saw there were two numbers after the decimal place.
Then I knew I had to times it by 1000 because there are 1000 grams in a kilogram.
After I ended up with

7.35kg ->7350g->7350 points

8.20kg->8200g->8200 points

6.45kg->6450g->6450 points