1.54 In the Aba tribe, there are two letters. It is known that in this language, no word is the prefix of another word. Can the dictionary of this tribe's language contain: 3 words each with 4 letters, 10 words each with 5 letters, 30 words each with 6 letters, and 5 words each with 7 letters?
[Solution] With two different letters, a total of $2^{7}=$ 128 different 7-letter words can be formed. However, since no word can be the prefix of another word, for a 7-letter word, its first $4,5,6$ letters cannot be the same as those of any existing word. There are a total of $3 \times 8+10 \times 4+30 \times 2=124$ such invalid 7-letter words. Therefore, only 4 valid 7-letter words are available, which is insufficient to meet the requirement.