The median of a set of 11 distinct observations is 17.5. If each of the largest 5 observations of the set is increased by 3, then the median of the new set

Given, 

The median of a set of 11 distinct observations is 17.5.

We know, 

Median of set of n observations = $$\left(\frac{n+1}{2}\right)^{th}observation$$

so, Median of set of 11 observations = $$\left(\frac{11+1}{2}\right)^{th}observation=\ 6^{th}observation\ $$

According to question, 

Each of the 5 largest observations of the set is increased by 3. 

But $$6^{th}\ $$ term of the data still remain the same. 

Median of data remain same as of orignal set. 

Hence, Option D is correct.