What is the rate and unit rate when you are using ratios

Which is the scale factor proportion for the enlargement shown?

The graph shows the decibel measure for sounds depending on how many times as intense they are as the threshold of sound. noise in a quiet room is 500 times as intense as the threshold of sound. what is the decibel measurement for the quiet room? 20 decibels28 decibels200 decibels280 decibels

Lowest fraction using common term 28/35