Question

You go to the doctor and he gives you 13 milligrams of radioactive dye. After 24 minutes, 4.25 milligrams of dye remain in your system. To leave the doctor's office, you must pass through a radiation detector without sounding the alarm. If the detector will sound the alarm if more than 2 milligrams of the dye are in your system, how long will your visit to the doctor take, assuming you were given the dye as soon as you arrived? Give your answer to the nearest minute.

You will spend ? minutes at the doctor's office.

Answer 1

56 min.

Answer 2

how? did you get it?

Answer 3

please:)

Answer 4

pert might help

Answer 5

ok:)

Answer 6

4.25 = 13(e^24t)

Answer 7

4.25/13 = e^24t

ln(4.25/13) = 24t

ln(4.25/13)
---------- = t
24

Answer 8

umm... t = rate lol

Answer 9

we use the rate to determine when 2 is the answer

Answer 10

2 = 13(e^rate(time))

Answer 11

time then equals:

ln(2/13)
------- = minimum time in office
rate

Answer 12

ok i see...:) hopefully i can get the next story prob right:) i have 17 of them:(

Answer 13

http://www.wolframalpha.com/input/?i=%28ln%282%2F13%29%29%2F%28ln%284.25%2F13%29%2F24%29

says 40.18 minutes

Answer 14

someone told me about this!:O! thanks!!

Answer 15

the website i mean haha

Answer 16

yeah, i just stumbled upon it one day while cleaning behind the fridge lol

Answer 17

lol