Question

You have 480 grams of a radioactive kind of tin. If its half-life is 10 days, how much will be left after 30 days?

Answers

Bosnian
After 10 days you have half left

After 20 days that's half of the half again = a quarter

After 30 days that's half of a quarter = an eighth


480 / 8 = 60 grams

Bosnian
Equation :

N( t ) = N( 0 ) * ( 1 / 2 ) ^ [ t / t( 1 / 2) ]

In this case :

N ( 30 ) = 480 * ( 1 / 2 ) ^ ( 30 / 10 )

N ( 30 ) = 480 * ( 1 / 2 ) ^ 3

N ( 30 ) = 480 * 1 / 8 = 60 grams
Bosnian
Also you can in google type:

half-life equation

and click : en.wikipedia
Anonymous
Suppose that a certain radioactive substance has a half-life of 20 years. If there are presently 2400 milligrams of the substance, how much, to the nearest milligram, will remain after 70 years?

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