You need to divide the amount he has by the serving size.
(3/4) / (1/6) =
= 3/4 * 6/1
= 18/4
= 4 1/2
He can make 4 1/2 servings.
That is going to be 48 for the first question because 6x8 equals 48
No it is NOT possible - that would mean the final angle would also have to be ninety degrees making it a square or rectangle. :)