An electron moving at a speed of 5 x 10 raise to power 6m/s was shot through a sheet of paper which is 2.1 x 10 raise to power 4cm thick. The electron emerges from the paper with a speed of 2 x 10 raise to power 6 m/s. Find the time taken by the electron to pass through the sheet.

Pls show full working and formular.

Enough, already