Someone known to the Quiz Master Shop team refuses to use a timer when timing anything that is cooking. Instead they insist on using the digital clock in the kitchen, which has hours and minutes, but not seconds.
So, for example, if something needs to cook for three minutes and it starts when the clock reads 17:12, they will wait until they clock reads 17:15 and then turn it off.
There is an obvious problem of being distracted by doing something else in the kitchen and missing the clock reading 17:15. And then only realising when it reads 17:18, and so overcooking whatever it is. Of course, a timer making a noise removes this problem.
However, there is another problem with the lack of precision; basically timing everything to the minute not the second. Clearly this is a small problem when timing something for 20 or 30 minutes, but in the example above it could be - the difference between a soft-boiled and hard-boiled egg perhaps.
So the puzzle is to work out the range of times that could result from the 17:12 to 17:15 example given above.
If the clock was seen reading 17:12 at 17:12:59 and then seen reading 17:15 at 17:15:00, this results in a time of 2 minutes and 1 second.
If the clock was seen reading 17:12 at 17:12:00 and then seen reading 17:15 at 17:15:59, this results in a time of 3 minutes and 59 seconds.
The second time is only two seconds short of being twice the first time!