Question

plzzzzz help me. . . .
The half-life of a radioactive substance is 5 minutes. how much of an original mass of 100 grams remains after half an hour?

Answer 1

but the choices are
a=14825
b. 24685
c. 15625
d. 25625

Answer 2

ok
let me try
after first half lif you will have 50 grams

after 30 minutes (6 half lives )
=100*(0.5)^6=1.5625

Answer 3

if \[\log_{36.2} =1.5587\]

Answer 4

what is the characteristics of\[\log=36.2\]