Question

how many 3 digits number can be formed out of digits 1,2,3,4,5,6. If repetition is not allowed​

Answer 1

Step-by-step explanation:

Total Number of Numbers which can be formed by numbers 1,2,3,4,5 (without repeating digitsi) = 5*4*3*2*! = 5! = 120.

Now, in half them unit's digit will be bigger than the ten's digit and in half of them it will be smaller.

Example: Let's say we have three digits 1,2,3. Total number of numbers without repeating digits = 3*2*1=6

Numbers with Unit's digit greater than the ten's digit

123, 213, 312

Numbers with Ten's digit greater than the unit's digit

321, 132, 231

So total Number of cases = 120/2 = 60

So, Answer will be B

Hope it helps!