Let's assume the number Sushil was thinking was 'x'
Now lets understand each part,
First, Sushil divides the number by 7, writing this in numbers will give,
![(x)/(7)](https://img.qammunity.org/2022/formulas/mathematics/high-school/or131zf4f505lmnq839e33z90b9i7dkv.png)
Sushil then adds 7 to digit, this will give
![(x)/(7)+7](https://img.qammunity.org/2022/formulas/mathematics/high-school/taemfdefon9ghwseqj770ku220epqkh4lv.png)
Sushil tells that the answer for the following equation is 12, so
![(x)/(7) + 7 = 12](https://img.qammunity.org/2022/formulas/mathematics/high-school/qt1jjtvw74z0xuayiox1h89mfiu8t96ex8.png)
Therefore the equation Sushil made is
![(x)/(7) + 7 = 12](https://img.qammunity.org/2022/formulas/mathematics/high-school/qt1jjtvw74z0xuayiox1h89mfiu8t96ex8.png)
Happy to help :)
If you need any help, feel free to ask