Total = Average × Number of people.<br><br>&bull; Total money of 4 people = $5.50 × 4 = $22<br>&bull; Aaron + Julian = Total − (Issac + Dick)<br>&bull; Aaron + Julian = $22 − $12 = $10<br>&bull; Average of Aaron and Julian = $10 ÷ 2 = $5<br><br>Final Answer: $5