Answer:
3/5
I am pretty sure that this is supposed to say 1/4 of the bottle to be shared with a friend...
Explanation:
So we have 20 ounces, we pour 1/4 of that to a friend. So 20/4=5 and then you took away 1/4 so, 20-5=15. Now we have 15 ounces left. Then you pour out 3 ounces which leaves us with 12. if you turn that into a fraction it would be 12/20 now all you have to do is simplify.
=

(12÷2=6) (20÷2=10)
=

(6÷2=3) (10÷2=5)
In conclusion, the answer is 3/5