Given:
Serenity picked 75% of the apples of a tree in her backyard.
She picked 30 apples.
To find:
The number of apples on the tree in the beginning.
Solution:
Let x be the number of apples on the tree in the beginning.
Serenity picked 75% of the apples of a tree in her backyard.
Number of apples picked = 75% of x
=
![(75)/(100)x](https://img.qammunity.org/2022/formulas/mathematics/college/c35nvdkuajuegbwcmjp4ia9avdxdyh5n51.png)
=
![(3)/(4)x](https://img.qammunity.org/2022/formulas/mathematics/college/qpw1vz6xv6t2s0tv8g3pqu8dejypfrd7n7.png)
She picked 30 apples.
![(3)/(4)x=30](https://img.qammunity.org/2022/formulas/mathematics/college/ky3ghal5xqxpoz3dvxzuen6yfzle0b1rsk.png)
Multiply both sides by 4.
![3x=4* 30](https://img.qammunity.org/2022/formulas/mathematics/college/c2n764r9xmnmc2wqwvqg1i70r6vnah3fyl.png)
![3x=120](https://img.qammunity.org/2022/formulas/mathematics/college/c5glg4ylxybus1hlv2ix67k37u5qma23qk.png)
Divide both sides by 3.
![x=(120)/(3)](https://img.qammunity.org/2022/formulas/mathematics/college/9zalnsqokkrunqvm1sh58wz1j605uh0y1i.png)
![x=40](https://img.qammunity.org/2022/formulas/mathematics/college/nn7y2uycpmg58bled5cv4qqsg5nzwny87y.png)
Therefore, the number of apples on the tree in the beginning is 40.