There are far too many variables. The main one is probably the traffic situation: how much traffic is there on the roads, how frequent are intersections with red lights, how bad are the traffic jams? The second most important variable is the terrain: is it flat or hilly, or all downhill, or all uphill? Then your physical condition is important, but I think anyone who doesn't just consider 25 miles an impossible distance to ride is in good enough physical shape to ride it in a decent amount of time. The type of bike you have might make some difference.

If you have luck on your side (i.e., if you can find a good route with few stops and relatively flat terrain), you'll probably be able to make it in 1.5 hrs under normal conditions. A couple of problems are these however:

1) You'll probably need some time to park your bike, clean up and change unless your job is like mine (I teach cycling right now - yay! - so I work in the clothes I wear on my commute and parking a bike means just rolling it into the room we're based in anyway).
2) If you ever get any sort of problem such as a flat tire - you'll be late.