You should not be using three equations for someone who is attempting a Primary 3 question. The most basic of algebra is only covered in Primary 6.

If it gets the job done, why not? There is no one right method when it comes to learning.

Whilst the method works, it’s probably going to be difficult to be processed in the thoughts of a Primary students who are taught to draw model diagrams, considering that a Primary 3 student is still relatively new to the field of problem sums.

As a side note, the author has reposted the same question again in a slightly newer post.

Thanks

Thanks