   Directions: The questions are based on the 5 four-digit numbers given below.

2764  7983  9862  5493  6278
Important for :
1
If in each number, all the composite digits are changed to their just previous prime number and all the prime digits are changed to their just next composite number then how many times '7' is repeated in the new sequence?
» Explain it
A
Given Sequence: 2764  7983  9862  5493  6278

New Sequence:   4853  8774  7754  6374  5487

Here '7' is repeated 6 times in the new sequence.

Note- Prime digits are colored with bold red and Composite digits are bold black.

Hence option A is correct.
2
If first and third digits of each number are interchanged and then numbers are arranged in ascending order then which of the following will be the second number from right end?
» Explain it
C
Given Sequence: 2764  7983  9862  5493  6278

New Sequence:   6724  8973  6892  9453  7268

Ascending order:6724  6892  7268  8973  9453

Here second number from right end is "8973" which represents "7983".

Hence option C is correct.
3
If all the digits are arranged in descending order within the number, then which of the following are the second greatest and the second lowest number respectively?
» Explain it
D
Given Sequence: 2764  7983  9862  5493  6278

New Sequence:   7642  9873  9862  9543  8762

Here the second greatest number is '9862' which represents "9862".
The second lowest number is '8762' which represents "6278".

Hence option D is correct.
4
If all the digits are arranged in ascending order within each of the numbers, how many such numbers are there in the new arrangment in which the positions of all the digits get changed within the number?
» Explain it
C
Given Sequence: 2764  7983  9862  5493  6278

New Sequence:   2467  3782689  3459  2678

Only one number is there in the new arrangment in which the positions of all the digits get changed within the number.

Hence option C is correct.
5
If all the digits are arranged in ascending order within each of the numbers and the product of first two digits of each new number is caculated, which of the following original number gives an odd number as resultant?
» Explain it
D
Given Sequence: 2764  7983  9862  5493  6278

Ascending order: 2467  3789  2689  3459  2678

product of first two digits: 8  21  12  12  12

Here after changing all digits of "7983" in ascending it gives "21" as resultant which is an odd an number.

Hence option D is correct.