Here's my take on this one:
1. Beatriz is the oldest 2. Ana is not the oldest 3. Celia is not the youngest
Let's assume that 1 is true......... then 2 is false........but this is impossible because Beatriz and Ana would both be the oldest - a contradiction......so T F F isn't a possibiity
Let's assume 2 is true.........then Ana could be the second oldest or the youngest. Assume that she is the second oldest.......so 3 is false and Celia is the youngest.......but 1 is also false.......which means that Beatriz could be the second youngest [ violating our assumption]........or the youngest - also impossible because we know that 3 is false and Celia is the youngest
And Ana can't be the youngest if we assume 2 is true, because 3 is false......Celia is the youngest in this scenario.......
So F T F isn't possible, either
This leaves FFT as the only possibility.......assume that Celia is the oldest.....then, since 2 is false, Ana would also have to be the oldest........and this is a contradiction
Assume Celia is the second oldest........then, since 2 is false, Ana is the oldest.......and since 1 is also false, Beatriz would be the youngest in this scenario
Thus
FFT is the only possibility and the correct order is A - C - B
