Given:
Mary spent 30% of her budget in groceries.
She spent 42$ on groceries.
To find:
The total amount of her budget.
Solution:
Let x be the total amount of the budget.
Then, the amount spent on groceries is 30% of x.
![(30)/(100)x=0.3x](https://img.qammunity.org/2022/formulas/mathematics/high-school/dp735oalnl5kmk7u7hyl7cce6qddeluyst.png)
She spent 42$ on groceries.
![0.3x=42](https://img.qammunity.org/2022/formulas/mathematics/high-school/kq0yfhv5wa2kfjfac40o91fvdbko33l3fl.png)
Divide both sides by 0.3.
![x=(42)/(0.3)](https://img.qammunity.org/2022/formulas/mathematics/high-school/ydnj0319ul7f5j9e57z4gd2rk4u7y1wc67.png)
![x=140](https://img.qammunity.org/2022/formulas/mathematics/high-school/jhvq5s9ten7ipx091gu3sj2wr9zajmegut.png)
Therefore, the total amount of the budget is 140$.