Multi-level marketing "legs" investment rule
Jelly, &nbsp;12&nbsp; 9 bytes

ṢṚ×J$ṫ⁵&lt;Ṃ


A full program which accepts x T M and prints 0 if the peer is rewarded and 1 if not.

Try it online!

How?

ṢṚ×J$ṫ⁵&lt;Ṃ - Main Link: list of numbers, x; number, T   e.g. [100, 50, 77, 22, 14, 45], 180
Ṣ         - sort x                                          [ 14, 22, 45, 50, 77,100]
 Ṛ        - reverse                                         [100, 77, 50, 45, 22, 14]
    $     - last two links as a monad:
   J      -   range of length                               [  1,  2,  3,  4,  5,  6]
  ×       -   multiply                                      [100,154,150,180,110, 84]
     ṫ    - tail from index:
      ⁵   -   5th argument (3rd input), M   (e.g. M=3)      [        150,180,110, 84]
       &lt;  - less than T?                                    [          1,  0,  1,  1]
        Ṃ - minimum                                         0