The total weight of a flying saucer and a rubik's cube is 3.3 kg. The total weight of a flying saucer and a toy car is 4.9 kg. If the total weight of a toy car and a rubik's cube is 6.37 kg, find the total weight of the flying saucer, the rubik's cube and the toy car.
Let 1 flying saucer be 1 F.
Let 1 rubik's cube be 1 R.
Let 1 toy car be 1 C.

1 F + 1 R = 3.3 --- (1)
1 F + 1 C = 4.9 --- (2)
1 C + 1 R = 6.37 --- (3)

(1) + (2) + (3)
1 F + 1 R + 1 F + 1 C + 1 C + 1 R = 3.3 + 4.9 + 6.37
2 F + 2 R + 2 C = 14.57
2(1 F + 1 R + 1 C) = 14.57 

1 F + 1 R + 1 C = 14.57 ÷ 2
1 F + 1 R + 1 C = 7.285

 Total weight of the flying saucer, the rubik's cube and the toy car = 7.285 kg

Answer(s): 7.285 kg