How many four letter words are formed using the letters of the word PROBLEM? Choose the correct choice from the following answers:
A) 760
B) 800
C) 840
D) 880
E) 920
The number of letters in the given word is seven.   The number of four letter words that can be formed using these seven letters is 7P4   = 7 * 6 * 5 * 4= 
<gadget id="calculator">7 * 6 * 5 * 4</gadget>
<output>840</output>
840.   Answer: 840
<result>C</result>
How many four letter words are formed using the letters of the word PROBLEM?