The total weight of a toy rifle and a jigsaw puzzle is 2.7 kg. The total weight of a toy rifle and a toy plane is 4.3 kg. If the total weight of a toy plane and a jigsaw puzzle is 4.58 kg, find the total weight of the toy rifle, the jigsaw puzzle and the toy plane.
Let 1 toy rifle be 1 T.
Let 1 jigsaw puzzle be 1 J.
Let 1 toy plane be 1 P.

1 T + 1 J = 2.7 --- (1)
1 T + 1 P = 4.3 --- (2)
1 P + 1 J = 4.58 --- (3)

(1) + (2) + (3)
1 T + 1 J + 1 T + 1 P + 1 P + 1 J = 2.7 + 4.3 + 4.58
2 T + 2 J + 2 P = 11.58
2(1 T + 1 J + 1 P) = 11.58 

1 T + 1 J + 1 P = 11.58 ÷ 2
1 T + 1 J + 1 P = 5.79

 Total weight of the toy rifle, the jigsaw puzzle and the toy plane = 5.79 kg

Answer(s): 5.79 kg