Thank you for your replies, but I still don't quite understand. If from Samir's frame of reference, his clock advances 10 seconds and Maria's advances 12.5 seconds, isn't Maria's clock running fast, when it should be slow from Samir's view? According to my textbook, Samir should have observed...
Since for the two events of Samir starting the stopwatch, and the stopwatch reaching 10.0s, Samir and his stopwatch are stationary from his own frame of reference, I said it was the proper time and that delta t0 = 10s. Then the speed of the moving frame of reference was 0.6c. I thought placing...