We use work something out to describe the mental process of finding a solution. It's about using logic and knowledge. When we work something out we understand it, but we may not have done anything other than think so far.
We use solve something when the problem is overcome. This could be a mental process (solve a maths problem, for example) or something physical (solve a problem with the engine).
Hello May Thida Su,
The phrases are:
We use work something out to describe the mental process of finding a solution. It's about using logic and knowledge. When we work something out we understand it, but we may not have done anything other than think so far.
We use solve something when the problem is overcome. This could be a mental process (solve a maths problem, for example) or something physical (solve a problem with the engine).
Peter
The LearnEnglish Team