And śṛ is the substitute of śnu and there is the affix śnu after it, when a sārvadhātuka affix denoting an agent follows.,
Thus श्रु + श्नु + तिप् = शृ + नु + ति = शृणोति 'he hears'; शृणुतः: 'they two hear'.,
Adhyāya 3 · Pāda 1 · Rule 74
And śṛ is the substitute of śnu and there is the affix śnu after it, when a sārvadhātuka affix denoting an agent follows.,
Thus श्रु + श्नु + तिप् = शृ + नु + ति = शृणोति 'he hears'; शृणुतः: 'they two hear'.,