'How many different three-letter codes can be made from the letters {a,b,c,d,e}? How many of them start with ab?'
Added by Brittany J.
Step 1
Since we are allowed to repeat the letters, the formula is: n^r where n is the number of choices for each position (in this case, 5 letters) and r is the number of positions (in this case, 3). So, the total number of three-letter codes is: 5^3 = 125 Therefore, Show more…
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