mathematics - Find the Different Sugar Cubes

There are 10 Boxes, each contains 1000 sugar cubes. The sugar cubes in 9 of the boxes are 10 grams each and the other box has 9 gram cubes.

There is a digital scale that you can use it ONCE. (i.e. put something on the scale, turn it on and read the number)

Find the box with the 9 gram cubes.

Source: Fekraneh.ir

Answer

• Set number from 1 to 10 to each box.


• pick cubes from from boxes with the equal amount of number of each box, and put them on scale.


• 
  
  

  read the last digit of shown number on the digital scale, and subtract this amount from 10. (e.g. weight=543 grams => 10 - 3 = 7 )

  
  

  The signle digit result will lead us to the 9 gram cubes box