Question

During a science experiment, the bacteria doubled every hour. At the start ofJen's experiment, there were 200 bacteria in the petri dish. The next time Jenchecked there were 6,400 bacteria. How much time has passed? (Solve for h)200 • 2h=6400=a.) 3 hoursb.) 4 hoursc.) 4.5 hoursd.) 5 hours

Answer 1

SOLUTION

The equation for this question should be

$200\times2^h=6400$

Solving for h, we have

$\begin{gathered} 200\times2^h=6400 \\ \text{dividing both sides by 200 we have } \\ \frac{200\times2^h}{200}=\frac{6400}{200} \\ 2^h=32 \end{gathered}$

This becomes

$\begin{gathered} 2^h=32 \\ 2^h=2^5 \\ \text{cancelling bases of 2, we have } \\ h=5 \end{gathered}$

Hence the answer is 5 hours. The answer is option D