In a certain appliance store, each model of television is uniquely designated by a code made up of a particular ordered pair of letters. If the store has 20 different models of televisions, what is the minimum number of letters that must be used to make the codes?	Choose the correct choice from the following answers.
A) 5  B) 7  C) 8  D) 9  E) 10
If n is the number of distinct letters used to create the two lettered codes, then a total of n∗n=n^2 different codes can be created. We need n2≥20. The smallest n which fulfills this condition is n = 5.   5nswer 5
<result>A</result>
In a certain appliance store, each model of television is uniquely designated by a code made up of a particular ordered pair of letters. If the store has 20 different models of televisions, what is the minimum number of letters that must be used to make the codes?