Respuesta :
Assuming we start with one zombie that can infect others, we can calculate the total number of new zombies using a rule of three:
[tex]\begin{gathered} 1\text{ minute}\to4\text{ new zombies} \\ 5\text{ minutes}\to x\text{ new zombies} \\ \\ \frac{1}{5}=\frac{4}{x} \\ \\ x=4\cdot5 \\ x=20 \end{gathered}[/tex]After 5 minutes there will be 20 new zombies. Then, adding the first zombie that infected the others, we have a total of 21 zombies.
In the same way, if we start with x zombies, the total number of zombies after 5 minutes will be 21x (x starting zombies plus 20x new zombies).
