The increase is an exponential increase in a multiplier
[tex]100%+0.45%=100.45%[/tex] and as decimal 1.0045
Final Value = Initial Value × [tex] multiplier^{number of years} [/tex]
Final value = [tex]300(1.0045)^{60} [/tex]
Final value = 393 mg (to the nearest whole number)
Half life = 0.5 years
Final value = [tex]300(1.0045)^{0.5} [/tex]=301 mg