Answer:
Number of apples ate = 5
Step-by-step explanation:
Fact:
One of them always tells the truth, while the other always lies.
To find how many apples banana ate, we have to figure out who is lying between Ana and Banana.
Ana: "Banana ate ten apples yesterday, and he is telling the truth."
If Ana is telling the truth, that means Banana is also telling the truth because of the statement (... and he is telling the truth).
This is not possible as one of them must be lying. The only option left is that Ana is lying.
Since Ana is lying, it means banana is telling the truth.
Banana: "No, I ate five apples yesterday, and Ana is lying."
Number of apples ate = 5
