Questions

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.

Terylene and nylon are synthetic fibres produced by a process of polymerisation. Terylene is a polyester and nylon, a poyamide.

Silk is purely a natural product obtained from silk worms.

Rayon is a man-made material which consists of purified cellulose in the form of long fibres. Cellulose occurs in the cell wall of plants. Rayon fibre is chemically identical to cotton but has a shine like silk. Since it is  basically derived from a natural source (cellulose) it is called a regenerated fibre.

The missing number in the given number puzzle is "78".

Here the logic is the numbers are from 86 - 91 when we read upside down.

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?