Awinery has a vat with two pipes leading to it. the inlet pipe can fill the vat in 66 ? hours, while the outlet pipe can empty it in 1010 hours. how long will it take to fill the vat if both pipes are left? open?

The time taken to fill the vat can be found using the least common multiple [LCM]. Given that the first pipe fills the tank in 66 hours and the second one empty the tank in 1010 hours, the time taken to fill the tank will be:
LCM(66,1010)
=66*1010
=66,660 hours
the answer is:
66,660 hours

2. they have negligible mass.