An academic problem

In a high school gym class, all the girls are lined up against one wall, 
and all the boys against the opposite wall. Every ten seconds, they walk 
toward each other exactly half the remaining distance between them. 

A mathematician, a physicist, and an engineer are asked, "When will the 
girls and boys meet?" Mathematician: "Never." Physicist: "In an infinite 
amount of time." Engineer: "Well... in about two minutes, they'll be close 
enough for all practical purposes."