In that case (thinking my assumption is incorrect!!) I shall give you my ideas about the question. The answer 2.5 is correct.
; (using the rules of significant figures.)
Since it is given that the answer could be rounded to first decimal place 2.5 is also correct.
Hope this will help you.
P.S: If you felt angry about my previous post I am really sorry about it. But MHF does not encourage any of it's members to give exam help.