An earthling sits on a bench in a park eating a sandwich. It takes him 5 min to finish it according to his watch. He is being monitored by planet Zenga invaders who are passing earth at a speed of 0.90c .
a. Calculate how long the aliens reckon it takes an earthling to eat a sandwich.
b. The aliens in the spacecraft get hungry and start eating their sandwiches. It takes a Zengan 5 min to eat her sandwich according to Zengan clocks. They are actually being observed by earthlings as they fly over earth. Calculate how long it takes a Zengan to eat a sandwich according to earth clocks.