Answer: He bought about 6 sodas.
Step-by-step explanation:
Given: Tota cost of tickets = $ 78
Cost of each soda = $4.25
Total cost of sodas and tickets = 102.50
Let x = Number of sodas purchased
Then
[tex]78+4.25x=102.50\\\\\Rightarrow\ 4.25x=102.50-78\\\\\Rightarrow\ 4.25x=24.5\\\\\Rightarrow\ x= \dfrac{24.5}{4.25}\\\\\Rightarrow\ x\approx6[/tex]
Hence, he bought about 6 sodas.