Technetium-99m is used as a radioactive tracer for certain medical tests. It has a half-life of 1 day. Consider the function T
where T(d)=100(2)−d
is the percent of Technetium-99m remaining d
days after the test. Which expression represents the number of days until only 5% remains?

Select the correct choice.

Responses

A log202
the log base 20 of 2

B −log220
negative log sub 2 20

C log2120
log sub 2 1 over 20

D −log2120
negative log sub 2 1 over 20