I am looking for how to complete the following question so that it gives a unique solution. Maybe somebody can give a visual solution.

A lab contains experimental equipment. 24 items are ready to use and do not require additional settings. To start other items, you need to add water, turn electricity, rotate a handle, click a button, or remove an equipment bag.

At least one of equipment bag and buttons are available for 37 items.

There are 26 items that use at least one of water and electricity.

Handles are provided with 23 items.

Two items have 4 characteristics out of five (water or electricity, or a handle or a button, or an equipment bag).

How many items are there in the lab?

  • $\begingroup$ @hexomino, my tag is puzzle-creation, this tag was given by Randal'Thor. I would like to have unique solution and can add or remove some constraints. $\endgroup$
    – Nick
    Aug 6, 2020 at 11:17
  • 2
    $\begingroup$ The phrasing seems ambiguous to me. "Water and electricity are used in 26 items". Does that mean that 26 items use both, and if so, can there still be other items that use one of them but not the other? Or does it mean that there are 26 items that use at least one of water and electricity? $\endgroup$ Aug 6, 2020 at 12:12
  • $\begingroup$ @jaapscherphuis, you are right, I have updated two conditions on "at least one of...". I have edited the question. $\endgroup$
    – Nick
    Aug 6, 2020 at 12:41


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