How can detect if the letters are dropped in rect?

[AlexPhaser]

Hi, I'm developing a basic game. The functionality of the game is, once the page is loaded one objects will appear on the canvas like (apple, cat, dog etc...) on the left side and a bunch of letters will appear on the right side. The user will have to drag and drop the letters in a rect area(bucket). Once the user dragged matched letters with the object within bucket then next object will appear in the same area.

I have created, but this is not working properly. http://dothejob.in/kids-game/phaser-demo2/

Could anyone help me on this? here is the js file. http://dothejob.in/kids-game/phaser-demo2/js/game.js

I need to check the following things....How can detect if the letters are dropped in rect? and which letter is dropped in Rect?
 

Thanks
Alex