Since someone running twice as fast a mile as another person would mean they complete the mile in half as much time, this means Tony would run a mile in 6/2= <<6/2=3>>3 minutes since Tina's time was 6 minutes.
Since Tom is three times as fast as Tina, for the same reasons as above this means his time is 6/3= <<6/3=2>>2 minutes.
Altogether then, the total time for all three is then 6+3+2= <<6+3+2=11>>11 minutes.
#### 11