Questions

We will rewrite the formula as an equation.

2K + 2Cr + 7O = 0

The zero comes from there being no overall charge on the compound.

Each oxidation number is represented by the element's symbol.

Since this compound is not a peroxide or superoxide, the oxidation value for O is -2

K being in group 1 has a +1 charge and therefore has an oxidation number of K is +1

Now, by putting known values in we have:

2(+1) + 2(Cr) + 7(-2) = 0

2 + 2Cr -14 = 0

2Cr = +12

Cr = +6.

The logic in the given puzzle is 

4 + 4 = 4 * 4+1 = 4 * 5 = 20

5 + 5 = 5 * 5+1 = 5 * 6 = 30

6 + 6 = 6 * 6+1 = 6 * 7 = 42

7 + 7 = 7 * 7+1 = 7 * 8 = 56

Similarly

9 + 9 = 9 * 9+1 = 9 * 10 = 90.

Aravalli seperates the valleys of Luni and Mahi while Vindhyas seperate the valleys of Mahi and Narmada

If you want bonus points, make sure you address each side of this tricky two-part question. 

The first part is addressing how you make sure you greet each and every customer who enters the store, giving them personal attention.  

The second part is how you would actually greet them – what would you say to them? Would you alert them of your newest products, ask if they’re looking for anything in particular or need guidance while shopping, or alert them to who they can reach out to if they require any assistance in various departments?