The total weight of a toy plane and a rubber ball is 3.1 kg. The total weight of a toy plane and a toy house is 4.3 kg. If the total weight of a toy house and a rubber ball is 4.84 kg, find the total weight of the toy plane, the rubber ball and the toy house.
Let 1 toy plane be 1 T.
Let 1 rubber ball be 1 R.
Let 1 toy house be 1 H.

1 T + 1 R = 3.1 --- (1)
1 T + 1 H = 4.3 --- (2)
1 H + 1 R = 4.84 --- (3)

(1) + (2) + (3)
1 T + 1 R + 1 T + 1 H + 1 H + 1 R = 3.1 + 4.3 + 4.84
2 T + 2 R + 2 H = 12.24
2(1 T + 1 R + 1 H) = 12.24 

1 T + 1 R + 1 H = 12.24 ÷ 2
1 T + 1 R + 1 H = 6.12

 Total weight of the toy plane, the rubber ball and the toy house = 6.12 kg

Answer(s): 6.12 kg