Let marks obtained by N = x
M's marks = 0.80x
L's marks = 1.25 (0.80x)
K's marks = (0.90) (1.25) (0.80x)
= 0.9x
But 0.9x = 360 x = 400
Percentage of Marks obtained by N
= 400 x 100/500 = 80%