How can weed go away in two days?

Question

my friend smoked weed like 2 days before she got drug tested, and she passed, how did that happen? we didnt drink alcohol or anything. we didnt even do anything.

Answer 1

she got lucky, she only smoked a little bit, she's very skinny, she drank a lot of water and ran?

Answer 2

she definitely got lucky...  stays in the system anywhere from 30-90 days depending on how much is smoked and how often.  It also depends on whether they test urine or hair follicles as well.  if they were to run a different test, she may not be so lucky.

Peace