HSBC Permutation and Combination Quiz-1

Since to form a 5-digit number 0 cannot be placed at ten-thousandth position.

Therefore, the number of possible arrangements can be 4*5*5*5*5 = 2500

Number of ways = ¹⁰C₄ x ⁵C₂ = 21 x 100 = 2100

Total attempts possible with three rings = 5*5*5*5*5 = 3125

Out of 3125 attempts only 1 will be a successful attempt.
Therefore, total number of failed attempts  = 3125-1= 3124

Each of the 10 mangoes can be placed in any of the 5 boxes, that is each mangoes has possible 5 arrangements.

First mango can be arranged in 5 ways.

Second can be arranged in 5 ways.

There are total 8 alphabets in the “STRAIGHT” out of which only 2 are Vowels (A and I)

Number of consonants = 6

Let the position of letter be:

• (2) (3) (4) (5) (6) (7) (8)