Rs.640 is divided among A, B, and C such that A's share is four times of C's share and B's share is  thrice of C's share. Find C's share.

70 80 65 70

80

A   :    B  :    C = 4x : 3x : x ATQ, ⇒ 4x + 3x + x = 640 ⇒ x = \(\frac{640}{8}\) = 80  ⇒ C's share = x = 80