Speedy Eating

• Tom, Freddy, Bard, and Zoe can eat $5$ pies in $3$ minutes.
• Therefore, Tom, Freddy, Bard, Zoe, and their dopplegangers (or doubles) can eat $5\times 2 = 10$ pies in $3$ minutes.
• Then, Tom, Freddy, Bard, Zoe, and their dopplegangers can eat $12$ pies in $\frac {12}{10}\times 3 = \boxed{3.6}$ minutes.

Tom, Freddy, Barb, Zoe and their doppelgangers form a total of 8 individuals, meaning their current rate of pie consumption is 10 pies in 3 minutes (there are twice as many people as oppose to the initial rate). The solution to this problem is to find an equivalent rate (10 pies/3 minutes --> 12 pies/n minutes [n = variable]), and the 'conversion number' of these rates would be 1.2 (12/10 = 1.2). You would now apply this number to the number of minutes in the consumption rate (10 pies/3 minutes) to determine the time required to eat 12 pies (n). 3 * 1.2 = 3.6, forming the result: it takes Tom, Freddy, Barb, Zoe and their doppelgangers 3.6 minutes to consume 12 pies together.

Additional Formula:

5 pies/3 minutes = Initial Rate of Consumption --> 10 pies/3 minutes = Consumption rate (with doppelgangers)
12/(10/3) = 3.6 minutes (time required to consume 12 pies by Tom, Freddy, Barb, Zoe and their doppelgangers).