Let m,n≥3, bc52de695f77a7f939780026741465" title="Click to view the MathML source">(m−1)(n−1)+2≤p≤mn, and u=mn−p. The set a623c0faba03" title="Click to view the MathML source">Ru×n×m of all real tensors with size u×n×m is one to one corresponding to the set of bilinear maps a0f7a135fb0" title="Click to view the MathML source">Rm×Rn→Ru. We show that a6633c8461ad5f79" title="Click to view the MathML source">Rm×n×p has plural typical ranks p and a6903fb2405f646dfd08f2612976d6" title="Click to view the MathML source">p+1 if and only if there exists a nonsingular bilinear map a0f7a135fb0" title="Click to view the MathML source">Rm×Rn→Ru. We show that there is a dense open subset bc5a13e438fac" title="Click to view the MathML source">O of a623c0faba03" title="Click to view the MathML source">Ru×n×m such that for any a85f533432f7fba5b11b3f82d6a8d34" title="Click to view the MathML source">Y∈O, the ideal of maximal minors of a matrix defined by Y in a certain way is a prime ideal and the real radical of that is the irrelevant maximal ideal if that is not a real prime ideal. Further, we show that there is a dense open subset e9e74c8a89fe4554e20028030ccd0b9b" title="Click to view the MathML source">T of Rn×p×m and continuous surjective open maps e9a5b87345635826f14262b" title="Click to view the MathML source">ν:O→Ru×p and σ:T→Ru×p, where Ru×p is the set of bcdf6bedf99013c" title="Click to view the MathML source">u×p matrices with entries in R, such that if e587b25ca5" title="Click to view the MathML source">ν(Y)=σ(T), then if and only if the ideal of maximal minors of the matrix defined by Y is a real prime ideal.