The final answer is A, or 1.25. If you'd like to see the steps, then read below.
First, plug in all of the known information. 2(18) + 2(1.5) + x = 10 + 30.25. You get this equation because only one ticket costs 18 dollars so you multiply 18 by 2. Same thing with the ice cream. Using x as a variable for the soda since it is the unknown value. The total cost for Amy was 10 dollars and the total cost for Mike was 30.25 dollars. First, simplifying the parentheses using the order of pemdas, 2(18) = 36. 2 x 1.5 = 3. The equation now simplifies down to 36 + 3 + x = 10 + 30.25. Now adding together 36 and 3 you get 39 + x = 10 + 30.25. Now finally adding together 10 and 30.25, the total cost is 40.25. The equation now simplifying down to 39 + x = 40.25, the final step is to subtract 39 from 40.25 to isolate x. 40.25 - 39 = 1.25. The soda costs 1.25 dollars.