How many different 3 letter combinations can be created from the letters A,B and C?  Options:	A) 81	B) 3	C) 9	D) 27	E) 243
This is a case of number of arrangements possible with repetition.   Thus you have 3 options each for the 1st,2nd and 3rd letter giving you a total of   3*3*3= 
<gadget id="calculator">  3*3*3</gadget>
<output>27</output>
27 number of possible combinations.   Answer : 27
<result>D</result>
How many different 3 letter combinations can be created from the letters A,B and C?