Question

 how many 10 digits numbers can be formed without repeating any digit and the difference of the digits at equal distances from the beginning and the end is always 1

Answer 1

Step-by-step explanation:

Given  how many 10 digits numbers can be formed without repeating any digit and the difference of the digits at equal distances from the beginning and the end is always 1

• We need to find the number of 10 digit number that is formed without repeating any digit.  
• So using the numbers are 0,1,2,…………9 we need to form.
• So we get if first number is 0, second number is 0, we get as 9!, + 9! ……9 times.
• So we get 9 x 9!
• So the numbers can be  
•             (0,1), (1,2), (2,3),(3,4),(4,5),(5,6),(6,7)
• So the numbers will be
•              (0,1),(2,3),(4,5),(6,7),(8,9)
• So we have  
•            4 C1  2!, 4C1 2!, 3C1 2! 2C1 2! 1C1 2! + 4C1 2!, 3C1 2! 2C1 2! 1C1 2!
• So we have
•                 4C1 2! , 3C1 2!, 2C1 2!  2! (4C1 2! + 1)
•                (4 x 3 x 2) (2 x 2 x 2) (4 x 2 + 1)
• So Probability = (4 x 3 x 2) (2 x 2 x 2 x 2) (9) / 9 x 9!
•                        = 4 x 3 x 2 x 16 x 9 / 9 x 9 x 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1
•                         = 1  / 9 x 7 x 15
•                         = 1/ 945

Reference link will be

https://brainly.in/question/21074450

Answer 2

Answer:

1/945will be the correct answer