What is the Surname of Barbie Doll?

Can you figure out the logic I used to decide the order of the following words:
gun, shoe, spree, door, hive, kicks, heaven, gate, line, den

Replace all '*' with digits 1, 2, 3, 4, 5 and 6 to make below statement true.

* *
x *
=====
* * *

We are a group of eight brothers. We consider the weak, yet we protect the king in every battle. If we move ahead, we never turn back. Who are we?

I can be made.
I can be cracked.
I can be told.
I can be played.

Who am I?

I have Rs.50 and I spend it in the way as below.

I have a sore throat and a severe headache. I have four tablets with me that are identical to each other and they do not have any cover on them. There is no way I can identify which tablet serves what purpose. The only thing that I know is that two of these four tablets are for the throat and the remaining two are for the headache. To treat my condition, I must take 1 of each. What will I do now?

Jim and Sarah are in a long-distance relationship. Jim buys an engagement ring for Sarah and wants to mail it to her. Unfortunately, the only way to ensure the ring will be received is to place a lock on the package. Jim has locks and Sarah has locks, but neither has keys for each other’s locks. How can they make sure the ring isn’t stolen?

What do you see in the given picture?

Suppose we lay down two cups in front of you. One of the cups is filled with tea and the other one with coffee. Now we ask you to take a spoonful of tea and mix it with the coffee. At this moment, the coffee cup has a mixture of tea and coffee. You have to take that mixture (spoonful) and add it back to the tea.

Can you now tell if the cup of coffee has more tea or the cup of tea has more coffee?