Math
posted by Einstein .
dear Ms.Sue what do they mean when they say find the tiime lapse.

The time lapse is the difference between the beginning time and the ending time.
What is the entire problem? 
time lapse is the time between two events:
Your mom tells you to clean your room at 8AM. Three days later, she tells you again. The time lapse is three days.
Here, lapse is used in its dictionary meaning as "interval".
Example: my dog ate my sisters freshly baked biscuits. Five minutes later he died. The lapse was five minutes.