Two different numbers are taken from the set {0, I ,2,3,4,5,6,7,8, 9, 10).The probability that their sum and  positive difference, are both multiple of 4, is x55 then x equals

Let the two numbers are ' a ' and ' b '  According to the question a+b=4p and a−b=4q where p, q∈I⇒ 2a=4(p+q) and 2b=4(p−q)⇒ a=2I1 and b=2I2Hence both a and b must be even.  Hence n(S)=11C2 n(A)=(0,4),(0,8),(2,6),(2,10),(4,8),(6,10)=6∴ P(A)=6 11C2=655