please help me resolve find what method gives me a result for this

I have this mathematic problem: (124164a/300b/2360/.85)+(124164a/25b/2360/.85)+(124164a/55b/2360/.85)=3.81=(a/b/2360/.85)

And this is the result:a≈87.4514, b≈0.0114422

I payed for WolframAlpha Pro just to get this problem solved and understand how it worked and did not get an understanding after expanding, would love to have someone tell me how Wolfram got this result.