Answer:
Her weight before was 100kg.
Explanation:
This question can be solved using a rule of three.
Amy finds that her weight has decreased by 25%
So her weight is 100-25 = 75% = 0.75 of the original amount(what it was before).
Her current weight is 75kg.
Her previous weight was x, which is 100% = 1.
So
75 - 0.75
x - 1
Her weight before was 100kg.