Garudapurana 1.60.1

1.60.1

śrīgaruḍamahāpurāṇam- 60
hariruvāca /
ṣaḍāditye daśā jñeyā some pañcadaśa smṛtāḥ /
aṣṭāvaṅgārake cava budhai spatadaśa smṛtāḥ //

The glorious Garuḍa Mahāpurāṇa — 60.
Hari said:
Six [years] are known as the period of the Sun; fifteen are taught for the Moon;
eight for Mars; and seventeen are taught for Mercury;