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
![0.75x = 75](https://img.qammunity.org/2021/formulas/mathematics/college/h64a99xyacyo446updz735yengj3xn0pw6.png)
![x = (75)/(0.75)](https://img.qammunity.org/2021/formulas/mathematics/college/bjegly7jz6tlhy2oc2tvnbm7hjipw61jje.png)
![x = 100](https://img.qammunity.org/2021/formulas/mathematics/middle-school/7jwuekaefnphko2eg3u1jfljubzenyora7.png)
Her weight before was 100kg.