IIT JEE , AIEEE Forum - Mathematics , Analytical Geometry

rishikesh_anshu

the no can have either one 8 ,two 8 or three 8
case 1: three 8    888      1 way
case 2: two 8      ³C₂*9              ³C₂ for selecting 2 place for 8
                                                  and 9 values to fill third place
                                                 (excluding 8)
case 3:one eight    ³C₁*9*9    ³C₁ for selecting 1 place for 8
                                                  and 9 values to fill other place
                                                   (excluding 8)
Total= 1+³C₂*9 + ³C₁*9*9    =271

This is the general solution and can be extended further

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