half life - exponential growth (1 Viewer)

[stressedadfff]

anyone know how to solve the following?

18 A quantity of a certain radioactive isotope reduces from 300 g to 208 g in 30 minutes.
a Find the half life of this isotope. Give your answer correct to the nearest second.
b How much of this isotope is left after 2½ hours? Give your answer correct to the nearest gram.

 

[CM_Tutor]

Already answered: https://boredofstudies.org/threads/motion.395396/#post-7376714