Question 944395
From 1 and 3 we find Tom is not in the front or rear, so he must be in the middle.
ANSWER:  Tom is in the middle
From 1 and 2 we find Tom is not 19 or 20, so Tom is 18 years old.
ANSWER:  Tom is 18 years old
ANSWERS Tom sits in the middle and he is 18 years old.