How long does an 80 mg Oxycontin pill last?

If you swallowed an 80 mg Oxycontin pill, how long would it last? As opposed to chewing it up?

Thanks.
Please don't include answers telling me I can't take them. I have a prescription and I'm supposed to take them - it's not as if I bought them off of a drug dealer or something.

: http://alcoholdrugstreatment.info/how-long-does-an-80-mg-oxycontin-pill-last