Level 3
There were 3 similar big boxes of the same mass. There were another 4 similar small boxes of the same mass. The total mass of the big and small boxes was 90 kg. The mass of a big box was twice the mass of a small box. Find the total mass of a big box and a small box.
Level 2
The mass of a box and one bag of potatoes is 1280 g. The mass of the same box and 2 similar bags of potatoes is 2040 g. What is the mass of a bag of potatoes?