Who is right !?

It's the 2nd standard class of a well-known school . Teacher is teaching them how to do addition . She wanted to explain with example .


She asked Rahul : " I will give you one apple now . After some time , I will give you one more apple . After that , one more apple . Tell me how many apples you have now ? "


Rahul answered , 4 apples .


Teacher again repeated the question . This time also , answer is 4 . Teacher thought its better to try with some other colour fruit .


Again she asked : " I will give you one mango . After some time , I will give another . After some time , I will give one more . Tell me how many mangoes you have now ?"


Rahul replied 3 mangoes .


Teacher was happy . She knew that Rahul is an intelligent boy . Again she repeated the question with apples . Rahul answer is 4 !


Teacher was about to lose her temper . But she remained calm , asked Rahul why is he answering differently with apples and mangoes ?



Rahul said , " I already have an apple with me . So when you give 3 apples , totally I have 4 apples . I don't have mangoes with me . So when you give 3 mangoes , that is the number of mangoes I have with me now !! " 



Who is right ?!!