The total weight of a jigsaw puzzle and a rubber ball is 3.3 kg. The total weight of a jigsaw puzzle and a toy plane is 5.4 kg. If the total weight of a toy plane and a rubber ball is 5.03 kg, find the total weight of the jigsaw puzzle, the rubber ball and the toy plane.
Let 1 jigsaw puzzle be 1 J.
Let 1 rubber ball be 1 R.
Let 1 toy plane be 1 P.

1 J + 1 R = 3.3 --- (1)
1 J + 1 P = 5.4 --- (2)
1 P + 1 R = 5.03 --- (3)

(1) + (2) + (3)
1 J + 1 R + 1 J + 1 P + 1 P + 1 R = 3.3 + 5.4 + 5.03
2 J + 2 R + 2 P = 13.73
2(1 J + 1 R + 1 P) = 13.73 

1 J + 1 R + 1 P = 13.73 ÷ 2
1 J + 1 R + 1 P = 6.865

 Total weight of the jigsaw puzzle, the rubber ball and the toy plane = 6.865 kg

Answer(s): 6.865 kg