Question

Last week the number of bacteria in a petri dish was 2.25×102. This week the number of bacteria in the petri dish is 2.75×105. How many times more bacteria are in the petri dish this week? Round the decimal to the nearest tenth. There are __ × 10__ times more bacteria in the petri dish this week compared to last week.

Answer 1

(2.75 x 10⁵ ) / (2.25 x 10² )

= (2.75 / 2.25) x 10⁵⁻²

= 1.2 x 10³ times .

(That's 1,200 times as many.)

Answer 2

Answer: There are $1.2\times10^3$ times more bacteria in the petri dish this week compared to last week.

Step-by-step explanation:

Given: Last week the number of bacteria in a petri dish = $2.25\times10^2$

This week the number of bacteria in the petri dish =$2.75\times10^5$

Now, the number of times more bacteria are in the petri dish this week will be :

$\dfrac{2.75\times10^5}{2.25\times10^2}\\\\\\=\dfrac{2.75}{2.25}\times10^{5-2}\ \ \text{Since} , a^m\times a^n=a^{m+n}\\\\\\=1.22222222222\times10^3\approx 1.2\times10^3$

Hence, There are $1.2\times10^3$ times more bacteria in the petri dish this week compared to last week.