Thank you for the opportunity to help you with your question!
The first question to ask is: "If you combine 3 liters of natural oil and 4 liters of synthetic oil, how many liters of oil (natural or synthetic) do you have?
Answer:3 + 4 = 7.
So, this means that 448 liters of Petrolyn oil must be 3/7 natural and 4/7 synthetic. That is, there are (3/7) * 448 = 3 * 64 = 192 liters of natural and (4/7) * 448 = 4 * 64 = 256 liters of synthetic. Can U check this answer? YES. 192 + 256 = 448!
Please let me know if you need any clarification. I'm always happy to answer your questions.