If a code word is defined to be a sequence of different letters chosen from the 10 letters A, B, C, D, E, F, G, H, I, and J, what is the ratio of the number of 7-letter code words to the number of 4-letter code words?  Select the correct option
A) 80
B) 90
C) 100
D) 110
E) 120
Method #1: Using the permutation formula   # of 7 letter code words:   nPr = n! / (n – r)! = 10! / (10 – 7)! = 10*9*8*7*6*5*4   # of 4 letter code words:   nPr = 10! / (10 – 4)! = 10*9*8*7   # of 7 words / # of 4 words = (10*9*8*7*6*5*4)/(10*9*8*7)= 
<gadget id="calculator">(10*9*8*7*6*5*4)/(10*9*8*7)</gadget>
<output>120</output>
120   120
<result>E</result>
If a code word is defined to be a sequence of different letters chosen from the 10 letters A, B, C, D, E, F, G, H, I, and J, what is the ratio of the number of 7-letter code words to the number of 4-letter code words?