It requires 10,000 calories to heat one liter of water from 30 degrees C to 40 degrees C
Exactly.
Now we should consider that if we want to know how quickly you did that in your head, we'd have to measure it in seconds or milliseconds. And seconds are a metric unit of measure. If you really hate metric, you'll need a different kind of watch. The Indian ghurry is a unit of time measure that you could use if you really want to get away from metric.
