What day would it be on $1$st March $2020$?

In the following letter series, one letter is missing shown as by a question mark(?). Select the missing letter from the given options.

$\mathrm{D}, \mathrm{G}, \mathrm{K}, ?, \mathrm{V}$

Two-thirds of my current age is the same as three-fourth of that of one of my cousins.

My age three years ago will be his age four years hence. My current age is _____ years.

Consider the given statement and decide which of the following statement is sufficient to answer the question.

How long will  $\mathrm{X}$ take to build the wall?

Statements:

$1$. $\mathrm{X}$ and $\mathrm{Y}$ together build the wall in $8$ days.

$2$. $\mathrm{X}$ takes $5$ days more than $\mathrm{Y}$ to build the wall.