I like this a lot, but I think the resolution may be a little too easy in practice. The target number is not that hard to hit with a relevant secret, so the tableplay may be too snappy for the timer values especially with pausing involved. This could also be very cool as some kind of express game where you have 30 minutes to solve 3 problems, and no ability to put time back on the clock. It could also be very interesting if expanded out further with time being added/subtracted during play. Really neat ideas.