A certain stock exchange designates each stock with one-, two-, or three-letter code, where each letter is selected from the 26 letters of the alphabet. If the letters may be repeated and if the same letters used in a different order constitute a different code, how many different stocks is it possible to uniquely designate with these codes?
a] 2,951
b] 8,125
c] 15,600
d] 16,302
e] 18,278
Correct ans - e any clue how?
a] 2,951
b] 8,125
c] 15,600
d] 16,302
e] 18,278
Correct ans - e any clue how?
