1 cant be in units place
If 2 in units place 1 has to be in tens place
We can have 3×2×1 = 6 possible numbers here
If 3 is in units place than we can either 1 or 2 at tens place
Then we have 3×2×1×2 for the rest of the slots = 12 numbers
If 4 at units place we can have 1, 2 & 3 at tens
For 1, 2 & 3 we have 3×2×1×3 = 18 numbers
Similarly for 5 at units place we have 3×2×1×4 = 24 numbers
Total such numbers = 6 + 12 + 18 + 24 = 60 numbers.
