Sam could buy 11 large pumpkins and 9 small pumpkins. He will only have 1.50 left over.
[tex]11 \times 6.00 = 66.00 \: price \: for \: large \\ 9 \times 2.50 = 22.50 \: price \: for \: small \\ 66.00 + 22.50 = 88.50 \: total \: price \\ 90.00 - 88.50 = 1.50 \: left \: over[/tex]