Question

The number of bacteria in a certain culture doubles every hours. If there were $30$ bacteria present in the culture originally, how many bacteria will be present at the end of $2^{nd}$ hour, $4^{th}$ hour and nth hour?

Answer 1

No. of bacteria present originally $=30$

$\therefore$ No. of bacteria present at the end of $2^{nd}$ hour $=30\times (2{)}^2$

$=120$

$\therefore$ No. of bacteria present at the end of $4^{th}$ hour

$=30\times (2{)}^4$

$=480$

$\therefore$ At the end of $n^{th}$ hour = $30\times 2^n$