Question 452628
a/2+a/3-a/4=1
6a+4a-3a=12
7a=12
a=12/7
a=1 5/7 minutes with both faucets and the drain open

It would take both the hot and cold running together
a/2 + a/3=1
3a+2a=6
5a=6
a=6/5 minutes
a= 1.2 minutes with both faucets and the drain closed.

so it takes a little longer because the drain is open