It shouldnt be consecutive ,.... so we can divide the numbers into 2 parts containing 10 values each
one part contains even numbers and other part contains odd numbers
by this, in the two parts we dont have numbers that are consecutive
now forming sets of threee numbers from these two parts we get
10C3 ways from part 1 and 10C3 ways from part 2
so 10C3 * 10C3 =14400