amanvermagmat wrote:
Set S has N terms in it, and K is the highest term, which is not a multiple of 5.
Set S = {5,10,15,.............,5N,K}
=> 5N is the highest multiple of 5 in the Set, and K is greater than 5N as per the constraints in the question
=> K > 5N
Since K has to be the largest term in the set, and 5N has to the largest multiple of 5 in the set, we can write the equation as
5N + 5 > K > 5N
E.g.
S = {5,10,15,20,21}
Here K = 21
5N = 20 (The largest multiple of 5 in the set) => N = 4 (# of Multiples of 5)
Does this help?
The question does not say that K is one of the terms of set S. It clearly says that S consist of all positive multiples of 5, which are less than K. In your example above, S will be S={5,10,15,20} and K will be 21, separate from the set.
I get the point that K/5>48, so K>5x48, so there should be at least 49 terms in K, greater than 48. But I don't understand why official answer says K could equal to at least 48, there is NO >= sign![/quote]
Hi The official answer does not say that K is equal to at least 48, it rather says that 'N' is equal to at least 48.
If K > 5*48, it means the positive multiples of 5 in K are at least 48 (starting from 5*1, 5*2, 5*3,..... to ... 5*48 at least).
And i agree with your first point, the example which was taken b{5, 10, 15, 20, 21} should not involve 21.. It should be {5, 10, 15, 20} and K=21 has to be separate from this set.[/quote]
Hi
amanvermagmatCan you please help me to clear my doubt.
Let \(S = {5,10,......., 5n}\)
\(5n < K\)
As per question, Mean is not divisible by 5. May I know how is it possible?
Sum of the Set S = \(\frac{n(5+5n)}{2} = \frac{5n(n+1)}{2}\)
Mean = \(\frac{5(n+1)}{2}\)...
So irrespective of n, mean is always divisible by 5.Am I Missing anything here?