The next roll will be his 11th roll.
The total on this tenth roll to have an average of 3 is 33, because 3 * 11 = <<33=33>>33
His current total is 31 because 1 + 3 + 2 + 4 + 3 + 5 + 6 + 1 + 4 + 2= <<1+3+2+4+3+5+6+1+4+2=31>>31
He needs to roll a 2 because 33 - 31 = <<33-31=2>>2
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