set 25 q 11

Lets assume no can be written as xxy

for first position you can have 9 different nos
Second position you would have only 1 possibility
third position you can have 8 possibility

so total is 9*8 = 72

Positions of x and y are interchangeable so no can be xxy, xyx, yxx - 3 ways

Total = 72*3 = 216

What's the OA

thanks a ton

I think ans should be E

say the repeated digit br R & the other digit be N

there are 3 possible arrangements for the nos

RRN
RNR
NRR

now if we tak case 1 we have

1st repeated digit R can be selected in 9 ways (0 excluded)
2nd repeated digit can be selected in 1 ways (same as we selected for first)
so 3rd digit i,e N can be selected in 8 ways

so total nos of ways is 9*1*8 =72 ways

same will come out for the other two arrangements

so total is 72+72+72 =216 ways

OA is E