question_answer

The number of ways to fill each of the four cells of the table with a distinct natural number such that the sum of the numbers is 10 and the sums of the numbers placed diagonally are equal is

A) 4                     

B) 8

C) 24                   

D) 6

Correct Answer: B

Solution :

[b] The natural number are 1, 2, 3, 4, clearly, in one diagonal we have to place 1, 4 and in the other 2, 3,. The number of ways in (i) is \[2!\times 2!=4\] The number of ways in (ii) is \[2!\times 2!=4\]. Therefore, the total number of ways is8.