your older twin born only 15.0 minutes before you, boards a spaceship and travels out among the stars at 2.436699 x 10^8 m/s. according to your watch they spend 60.0 minutes travelling at that speed. when they get back to earth they are no longer 15 minutes older than you. who is older than who and by how much

Awoodchuck would chuck all the wood he could chuck if a woodchuck could chuck wood.

Distance covered = speed x timethe distance traveled going against the stream = distance traveled with the stream.therefore it is the speed and the time that are the variables.as he travels the same distance both ways, speed x time is the same for each way.going upstream his speed is 4 kph; going downstream his speed is 6 kph.therefore we have two simultaneous equations: time upstream x 4 = time downstream x 6time upstream + time downstream = 60 minutestherefore we have the equation: time upstream = 6/10 hour, time downstream therefore = 4/10 hour.distance traveled at 4km/hr in 6/10 hour = 24/10 = 2.4km.check: distance traveled at 6km/hr in 4/10 hour = 24/10 = 2.4km.