CPU always generates a logical address.
CPU generates a logical address consisting of two parts
1.S=SEGEMENT NUMBER
2.D=SEGEMENT OFFSET
Assuming Memory is word Addressable,
Number of Segements=64
S= Bits used to represent Segement Number=$\large \log 64{\color{Red} }$=$6$ bits
D=Bits used to represent Offset
Since Maximum segement size is 512 words
D=$\large \log 512{\color{Red} }$=$9$ bits.
Length of Logical address=S+D=$6$+$9$=$15$ BIts.
Hope it helps. $:))$