I Need To Get Into My Weight Class...Quick

I am a 17 year old femail and i am in the ARMY my only issue is that i cant take my ASVAB test untill i am in my weight class....the thing is that if i dont lose this weight i am not going to be able to be in the ARMY any longer......Does anyone know how to lose a quick 20lb's?....******
Thankyou all so much

**edited by moderator**



- Megan