.
First part of the condition says
x + y + z = 243, (1)
where x is the first quantity, y is the second and z is the third.
Second part of the condition gives these equalities
=
, (2)
=
(3)
From (2), y =
, z =
=
= 2x.
Substitute it into (3), and you will get
= 243, or
4.5x = 243.
x =
= 54.
Then y =
= 81 and z = 2x = 108.