Solution:

Tapti River, ancient original name Tapati River, is a river in central India. It is one of the major rivers of peninsular India with a length of around 724 kms. It is one of only three rivers in peninsular India that run from east to west – the others being the Narmada River and the Mahi River. The principal tributaries of the Tapti River are the Mindhola River, Girna River, Panzara River, Waghur River, Bori River and Aner River.

Son is the tributary of Ganga, other tributaries:
Ramganga, Gomti, Ghaghara, Gandak, Kosi and Mahananda from left bank and Yamuna, Tamsa.