Number of ways of selecting two integers 'a' and 'b' from the set{1,2,3,4,.....5n}, n€N so thata4-b4 is divisible by5?A)17n2+5n/2 B)15n2-17n/2 C)17n2-5n/2 D)15n2+17n/2

siri dhani , 14 Years ago

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