Sensible shopping

This is what happened @ school. My teacher was teaching basic division through money and shopping. There was a list of items given with its price.

Teacher - You have 2 rupees with you. Look at the items and tell what items you can buy from the shop

Teacher to student 1(reading from the list) - One aeroplane toy is 2 rupees, how many can you buy?

Student 1 - I will buy 1 aeroplane toy.

Teacher - good

Teacher - Paaduka, one ball costs 1 rupee. How many balls can you buy?

pAdukA - One!

Teacher - Wrong.. That's not the answer.

After a while my teacher came to me and asked if I understood what she was teaching. She explained everything and asked if I knew the answer.

pAdukA - I will buy one ball

Teacher - No.. that's not the answer. Why are you saying one again after listening to all that I explained

pAdukA - I want to buy only one ball and I will have one rupee left which I want to use to buy something else from the shop. Why buy 2 balls??

Sensible right??