First, we need to determine how much the entire meal costs before we can determine the tip. We perform 10+20+30=<<10+20+30=60>>60 dollars worth of food.
Now we need to find out how much the total tip to be paid is, by multiplying 60*.2=12 dollars in tips.
Since they want to split this evenly amongst three people, this works out to 12/3= <<12/3=4>>4 dollars in tips per person.
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