Step-by-step explanation:
9.1
....................
⇒

is a improper fraction.

as a mixed number would be 4

⇒10 x 4 = 40
⇒40 + 9 = 49

= 4
⇒ANSWER = 4
Automatically we know that he is wrong because even if we round it to make it a friendly number (lets say 1) it will still not equal 3 1/2
he has them for 3 1/2 days
even 1+1+1= 3 it still isnt enough and you arent even supposed to round
That is why he is wrong :) hope this helped