Phaladeepika
नृणां वर्षशतं ह्यायुस्तास्मींस्त्रेधा विभज्यते । अल्पं मध्यं दीर्घमायुरित्येतत्सर्वसम्मतम् ॥ ७॥
A hundred years are generally reckoned as the period of life for human beings. The division of this period into three portions constitute respectively the life period of a shori-lived, middle-aged and longlived person and is recognised universally.
english translation
nRNAM varSazataM hyAyustAsmIMstredhA vibhajyate । alpaM madhyaM dIrghamAyurityetatsarvasammatam ॥ 7॥
hk transliteration by Sanscript