chemistry
posted by koteswaramma .
a radioactive substance decays 10% in 5 days. The amount remains after 20 days?
Respond to this Question
Similar Questions

Math/Calculus
After 5 days, a particular radioactive substance decays to 37% of its original amount. Find the half life of this substance. Is this right? 
Algebra
Andrew measures the amount of a very unstable substance to be 100 moles. The halflife of this substance is 3 days (after 3 days, half is gone). Write an exponential function that models this situation where y is the amount of substance … 
Calculus
The radioactive element polonium decays according to the law given below where Q0 is the initial amount and the time t is measured in days. Q(t) = Q0 ยท 2(t/140) If the amount of polonium left after 700 days is 45 mg, what was the … 
Physics
A radioactive substance decays from 2.0kg to 1.6kg in 156 days. How much will be left after 201 days? 
Calculus
Santr 109 (a fictitious substance) decays by about 6% every day. How much of a 84 pound sample remains after: (a) 7 days (b) 3 weeks (b) 48 days 
Science
If 15% of the radioactive material decays in 5 days, what would be the percentage of amount of original material left after 25 days? 
College Algebra
A radioactive substance decays in such a way that the amount of mass remaining after t days is given by the function m(t) = 9e−0.012t where m(t) is measured in kilograms. (a) Find the mass at time t = 0. 
College Algebra
A radioactive substance decays in such a way that the amount of mass remaining after t days is given by the function m(t) = 9e−0.012t b) How much of the mass remains after 49 days? 
math
The radioactive decay of a substance is expressed by A=A^0 e^ kt, where the initial amount A^0, decays to an amount A after t years. The positive constant k differs for each substance. Strontium 90 decays such that k=.028. Find out … 
Math algebra
The radioactive decay of a substance is expressed by A=A^0 e^ kt, where the initial amount A^0, decays to an amount A after t years. The positive constant k differs for each substance. Strontium 90 decays such that k=.028. Find out …