Samkhya Karika 46

एष प्रत्ययसर्गो विपर्ययाशक्तितुष्टिसिद्ध्याख्यः ।
गुणवैषम्यविमर्द्देन तस्य भेदास्तु पञ्चाशत् ॥ ४६ ॥

eṣa pratyayasargo viparyayāśaktituṣṭisiddhyākhyaḥ ।
guṇavaiṣamyavimarddena tasya bhedāstu pañcāśat ॥ 46 ॥

eṣaḥ=this; pratyaya=buddhi (intellect); sargaḥ=creation; viparyaya=ignorance; aśakti=weakness, infirmity; tuṣṭi=satisfaction, complacency; siddhi=attainment; ākhyaḥ=known as; guṇa=the three gunas; vaiṣamya=inequality; vimarddena=from (mutual) suppression; tasyaits; bhedāḥ=different forms; tu=indeed; pañcāśat=fifty

This (the group of sixteen – eight causes and eight effects as given in karikas 44 and 45) is a creation of the intellect, and is characterized by ignorance, incapacity, contentment and attainment. Due to the mutual suppression of the gunas due to their inequality, the different forms add up to fifty.