Question

Tom is 20 years old when he boards a spaceship that flies at 0.800c toward Planet X which is 12 lightyears away. Left behind on Earth is his twin brother Tim. Upon reaching Planet X, Tom immediately turns back and returns to Earth at a slower speed of 0.600c. What is the biological age of Tim upon Tom's arrival on Earth?

A. 55 yrs old
B. 45 yrs old
C. 40 yrs old
D. 50 yrs old

Answer 1