Question 1198532
Gallium-67 is used in nuclear medicine to help doctors locate inflammation and chronic infections.
 The patient is injected with a tracer (trace amount) that includes gallium-67, which collects in areas of inflammation and infection.
 The gallium-67 emits radiation that a special camera can detect. Gallium-67 has a half-life of 3.26 days.
- Give an exponential equation to represent the percentage of the original gallium-67 after t days.
:
{{{A = Ao*2^(-t/3.26)}}}, where
A = resulting amt after t time
Ao = initial amt
t = time of decay
3.26 = half life of the substance

To find the percentage, use 1 as the initial amt multiply the resulting decimal by 100
:
Gallium-67 is used in nuclear medicine to help doctors locate inflammation and chronic infections.
 The patient is injected with a tracer (trace amount) that includes gallium-67, which collects in areas of inflammation and infection.
 The gallium-67 emits radiation that a special camera can detect. Gallium-67 has a half-life of 3.26 days.
- After 4 days, how much percentage is remaining?


{{{A% = Ao*2^(-4/3.26)}}} * 100
A% = 42.72% remains after 4 days
: 
- After how many days, is 1% of the original Gallium-67 will remain? Round your answer to 2 decimal places 
{{{ 1*2^(-t/3.26)}}} = .01
using nat logs 
{{{(-t/3.26)*ln(2) = Ln(.01)}}}
:
t = {{{ln(.01)/ln(2)}}} * -3.26
t = 21.66 days