try 50 Challenging Problems In Probability by Mosteller. it starts pretty basic and works up slowly to a good foundation for learning probability theory in a ri

try 50 Challenging Problems In Probability by Mosteller. it starts pretty basic and works up slowly to a good foundation for learning probability theory in a rigorous way using very neat problems. https://www.amazon.com/Challenging-Problems-Probability-Solutions-Mathematics/dp/0486653552/ref=sr_1_1?ie=UTF8&qid=1537816101&sr=8-1&keywords=problems+in+probability https://www.amazon.com/Challenging-Problems-Probability-Solu...