"She can hear a pin drop a mile away." This is an example of -

• Hyperbole is an exaggerated statement or an extreme overstatement.
- Hyperbole used to create strong emotional response. 
- It can be positive as well as negative. 
- It can be a source of laughter. 
- It also can be a bitter criticism. 

• Some examples of Hyperbole:
- I'm so hungry I could eat a horse.
- She's as old as the hills.
- I walked a million miles to get here.
- She can hear a pin drop a mile away.
- I died of embarrassment.
- He's as skinny as a toothpick.
- She's as tall as a beanpole.
- It's raining cats and dogs.

Source: An ABC of English Literature - Dr M Mofizar Rahman