Answer:
Tom sits in the middle and he is 18
Step-by-step explanation:
On the table you will first mark off Tom from being in the rear, as well as being 19
You will mark off Tom and Roy from the 1st, which places Davis as 1st, you also know that Tom is neither 1st nor last, so he is in the middle.
Now you see that Roy is neither in the 1st nor middle, so he is last.
Last is also the 20 yr old, so Roy is 20yrs and last seat.
Tom is neither 19 or 20.
So Tom is in the middle and 18yrs old