Is the exact time it takes to evaluate 27 plus 72exact time it takes to evaluate 27+72 discrete or continuous?

Time is continuous.

 If it was possible to measure EXACTLY the time it takes a person (or group of people) to evaluate 27 + 72 (=99), the time(s) people took could be 2 seconds, 3 seconds, 2.5 seconds, 2.25 seconds, 2.22 seconds, 2.2199999 seconds... In other words, any value is possible when measuring "exact" time elapsed.

However, people are limited by the tools they use. There isn't a tool without limits in its ability to measure time elapsed. For example, is the stopwatch accurate to 1/100th of a second? 1/1000th of a second? At some point it reaches its limit. The constraints of the tool being used to measure are going to, in fact, cause data to be "discrete."

I'm 90% sure you're teacher is looking for "continuous" as the solution though. So don't bring up "discrete" unless you feel like you'll be able to confidently explain the second paragraph above.

I’d go with b hope it