Answer:
See Below
Step-by-step explanation:
Okay, I thinkkk what it is asking by what you summarzied for me issss:
They split the total time into four quarters. They then took (for the first quarter) the start time. Then when the first quarter ends and the second quarter starts is the "end" time.
They then subtract the start time of the second quarter from the end time of the first quarter.
I hope this helps, good luck! :D