A shipment of TV sets, some weighting 30kg each and the others weighing 50kg each, has a total weight of 880kg. if there are 20 tv sets all together, how many weigh 50kg?

Answer 1

Let's say the number of TV sets weighing 30kg each is x.
The number of TV sets weighing 50kg each is then 20 - x.
The total weight of the TV sets weighing 30kg each is 30x.
The total weight of the TV sets weighing 50kg each is 50(20 - x).
The total weight of all TV sets is 30x + 50(20 - x) = 880kg.
Expanding the equation gives 30x + 1000 - 50x = 880.
Combining like terms gives -20x + 1000 = 880.
Subtracting 1000 from both sides gives -20x = -120.
Dividing both sides by -20 gives x = 6.
Therefore, the number of TV sets weighing 50kg each is 20 - 6 = <<20-6=14>>14. Answer: \boxed{14}.