The total amount spent on food is $40 + $15 + $25 = $<<40+15+25=80>>80.
The service charge is $80 x 10/100 = $<<80*10/100=8>>8.
The tip is $80 x 5/100 = $<<80*5/100=4>>4.
So, Mr. Arevalo had to pay $80 + $8 + $4 = $<<80+8+4=92>>92 in all.
Therefore, his change will only be $100 - $92 = $<<100-92=8>>8.
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