Answer:
t = 4.7 days
Step-by-step explanation:
The half life formula is
N = No * e ^ (-kt)
Where No is the initial amount of the substance
N = 45 e ^ (-.1483 t)
We want 1/2 of the substance left
22.5 is half of 45 grams
22.5 = 45 e ^ (-.1483 t)
Divide each side by 45
1/2 = e ^ (-.1483 t)
Take the natural log of each side
ln(1/2) = ln (e ^ (-.1483 t))
ln(1/2) = -.1483t
Divide each side by -.1483
ln(1/2) / -.1483 = t
t=4.67395
Rounding to the nearest tenth
t = 4.7 days
