Troy bakes 2 x 16 = <<2*16=32>>32 brownie pieces.
75% of one pan is 16 x 0.75 = <<16*0.75=12>>12 pieces.
Guests eat 16 + 12 = <<16+12=28>>28 pieces.
This many guests eat the brownies ala mode 28 - 4 = <<28-4=24>>24.
This many scoops are eaten by the guests 24 x 2 = <<24*2=48>>48.
The guests eat this many tubs 48 / 8 = <<48/8=6>>6 tubs.
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