Sweet

Joanne and Josyne have monthly test at the school. Every month after the test, their mummy will give one sweet to those who can manage to get at least B.

Joanne is hardworking girl, she always scores A. Therefore, she almost guarantee will get one sweet every month.

Josyne is a not-so-hardworking girl. Sometimes she gets B, sometimes he gets C. So sometimes she can get sweet, but sometimes not. When she does not get any sweet, she will go to snatch Joanne's sweet, and they often end up with fighting.

In order to reduce the fighting and make them either they both have sweet or they both don't have, mummy comes out with an idea.

"If anyone of you can get B and above, both of you will get sweet," says mummy.

"It won't work," says daddy.

So, for the first month, Joanne gets A and Josyne gets B. Both get sweet.

For the following few months, Joanne gets A and Josyne gets C. Both still get sweet. 

Then Joanne begins to think, "why do I need to study so hard but Josyne does not study at all, she will still get a sweet?"

The next month, Joanne gets C and Josyne gets D. Both get no sweet.

Josyne begins to blame Joanne for not study hard. Joanne blames Josyne for not contributing to get any sweet at all.

For the next few months, both of them don't get any sweet anymore.