if ( bmi <= 18.5 ) will return a value thus none of the following statements will be checked.

Rejected for using outdated language version.

Forking is still possible, so no work is necessarily lost.

oh ye you are right my bad.

impossible

This won't actuall work properly. If you have 10 for example, all 3 options will be triggered

upon further exploration, it's because I change the argument arrays, and this makes the unit test expected calculation misbehave. Either the unit tests should be fixed (to at least display a meaningful error in that case...), or the instructions clarified.

Is there some issue with the random tests in ruby? I keep getting failures because it expects an empty array when I return an interleaved array. For example, in one of the random tests, the input was:
3 <<<<
t k 1 0 c l y <<<<
q x 5 <<<<
l 8 o s g a v <<<<
m v <<<<
j k s v r <<<<
b 4 s r f f 3 r <<<<
4 z 0 6 <<<<
<<<<
(each row is an array)
and I got the error message:
Expected: [], instead got: [3, "t", "q", "l", "m", "j", "b", 4, nil, nil, "k", "x", 8, "v", "k", 4, "z", nil, nil, 1, 5, "o", nil, "s", "s", 0, nil, nil, 0, nil, "s", nil, "v", "r", 6, nil, nil, "c", nil, "g", nil, "r", "f", nil, nil, nil, "l", nil, "a", nil, nil, "f", nil, nil, nil, "y", nil, "v", nil, nil, 3, nil, nil, nil, nil, nil, nil, nil, nil, "r", nil, nil]

The usage of "same" in the description can be a bit tricky to parse, but a look at the test cases sort of helps clarify things.

The description says, "...all of them (the other elements) are the same, except for one single number."

In your example case, although 2 is the single number, 1 and 3 are not all the same. Therefore, it would not be what the kata is testing for.

In other words, the kata is looking for examples that take on the template of: [x, x, x, x, y, x, x] or [y, x, x, x, x] but not [x, y, y, z, z, z, z, z, z].

Fixed typo, thx.

Small spelling fix: at the second line, fix "buting" to "buying".

Also, not an issue per se, but I think it'll be good to add using System and/or using System.Linq to the initial code.