Let A=[acbd] where a,b,c,d are prime.
Total number of matrices A formed =104
Let S be a matrix from set of matrices A such that S is singular.
For singular matrix ∣S∣=ad−bc=0⇒ad=bc
Number of singular matrices = All entries are same + only two prime number are used in matrix
then number of matrices with two prime numbers =(10×9)×2!=180
then number of matrices with one prime number =10×1=10
So required probability =10410×9×2!+10=100019=0.019