Answer:
She left a 15% tip.
Explanation:
Just do $10.99 (The original price, I believe.) and then the tip she gave. ($2.00)
And turn it into a percentage.
I know the other person already answered, 50% credits to them, because they only gave the "Answer:" part. (No offense if you're reading this.)
Hope this helped, and enjoy the little pun!
"The other person already answered 50%"