Let
x = {5, 10, 15, 20, 25, 30, 35, 40}.
define a relation

on x as follows. for
a, b is in x,

a

b
if b can be obtained from a by adding a (possibly empty) collection of dimes (10 cents) and quarters (25 cents). so, for example,
25

35, but 25

30.

list all minimal elements of
(x,

).
(enter your answers as a comma-separated list.)