Solve the Problem $$\mathrm { y } = \mathrm { y } 0 \mathrm { e } ^ { - 0.0002 \mathrm { t } }$$

Multiple Choice

Solve the problem.
-A certain radioactive isotope decays at a rate of 2% per 100 years. If t represents time in years and y represents the amount of the isotope left then the equation for the situation is $$\mathrm { y } = \mathrm { y } 0 \mathrm { e } ^ { - 0.0002 \mathrm { t } }$$ In how many years will
There be 94% of the isotope left?

A) 300 yr
B) 256 yr
C) 600 yr
D) 309 yr