Arthashastra
पञ्च दश रथस्य हस्तिनो वा, पञ्च च अश्वाः ॥
fifteen men or five horses to oppose a chariot or an elephant; and as many (fifteen) servants ( pádagopa) for a horse, a chariot and an elephant should be maintained.
english translation
paJca daza rathasya hastino vA, paJca ca azvAH ॥
hk transliteration by Sanscript