Answer:
20$ owed back
Explanation:
Let's understand this sentence by sentence.
On Saturday, Kelly borrowed $15 from her sister. The next day, she paid back $4. On Tuesday, she borrowed $9 more. How much money does Kelly now owe her sister?
"On Saturday, Kelly borrowed $15 from her sister." That means that she owes 15 dollars to her sister right now.
"The next day, she paid back $4." That means that she is now 4$ less in debt. So in total, she is 11$ in debt now. (Is that actually real debt?)
"On Tuesday, she borrowed $9 more." That means that she owes even more money again. To be precise, 9$ more.
So 11$ + 9$ = 20$ owed
20$ owed at the end