Question

The number of bacteria in a sample quadruples every 24 hours.There are 20 bacteria in the sample initially.Write an equation to find b,the number of bacteria in the sample after d days.

Answer 1

This is an exponential growth problem of the form:

F=Ir^t  we are told that the sample quadruples every day so

4=r^1 so

r=4 then the equation becomes:

F(t)=a4^t and we are told that the initial sample, a, is 20 so:

F(t)=20(4^t)  and if we let t=days=d

F(d)=20(4^d)