If the price of 6 pretzels is $5.10, first find the price of 1. After you've found the price for 1, find the price of 8 by multiplying it 8. Now, since two people are sharing the cost, each will pay half of the total
1. 6 pretzels = $5.10 => 1 pretzel = $5.10/6 = $0.85
2. 1 pretzel = $0.85 => 8 pretzels = $0.85 * 8 = $6.80
3. price paid by both Simon and Sofia: $6.80/2 => $3.40
Therefore, the total cost shared by Sofia and Simon for 8 pretzels is $3.40.
Hope that helps!