A security system records video footage. One minute of video requires 180 MegaBytes of storage. The recording system can store several hours of video footage. How much storage would be needed for 2 hours of video footage? (lk=1024):

The correct option is 21.1 Giga Bytes.

To find the total storage needed for 2 hours of video footage, we can break down the calculation into the following steps:

Step 1: Convert the total duration of the video into minutes.
We are given that the duration of the video is 2 hours. Since 1 hour consists of 60 minutes, the total duration in minutes is calculated as:

$2\times 60=120\text{minutes}$

Step 2: Calculate the total storage required in MegaBytes (MB).
Since 1 minute of video requires 180 MegaBytes of storage, 120 minutes of video will require:

$120\times 180=\mathrm{21,600}\text{MegaBytes (MB)}$

Step 3: Convert the storage from MegaBytes to GigaBytes (GB).
Using the binary conversion standard where 1 GigaByte is equal to 1024 MegaBytes (as indicated by the conversion factor 1k = 1024), we divide the total storage in MegaBytes by 1024:

$\text{Storage in GB}=\frac{\mathrm{21,600}}{\mathrm{1,024}}$

$\text{Storage in GB}\approx 21.09375\text{GigaBytes}$

Rounding this result to one decimal place gives approximately 21.1 Giga Bytes.