Question

All possible 6 digit natural numbers are formed using the digits 1, 2, 3, 4, 5 and 6 without repetitions. How many numbers so formed would have 2 ahead of 4 and 5?

Answer 1

240 numbers can be formed if 2 ahead of 4 and 5, in all possible 6 digit natural numbers are formed using the digits 1,2,3,4,5 and 6 without repetitions.

Step-by-step explanation:

Let make a group of 3 digits = 2, 4, 5

Here, 2 is ahead of 4 and 5

so it can be  245  or  254 in 2 ways

3 Position out of 6 can be filled by 3 others number in  ⁶P₃ ways

⁶P₃ = 6! / 3! = 120

Then,  120 X 2 = 240

Therefore,

240 numbers can be formed if 2 ahead of 4 and 5, in all possible 6 digit natural numbers are formed using the digits 1,2,3,4,5 and 6 without repetitions