What brings you down but never up?

What does this rebus means ?

When we see 2 but call 10?

Prove that twice of ten is the same as twice of eleven.

What happened when the wheel was invented?

Given that

(78)^9 = 6
And (69)^4 = 11

Can you find out

(99)^2 =?

(Note: This is Logical, not Mathematical)

1 + 9 + 8 = ?
considering, 28 + 8 + 92 = 10

A prisoner is told: "If you tell a lie, we will hang you and if you tell the truth, we will shoot you." What did the prisoner say to save himself?

My thunder comes before the lightning; my lightning comes before clouds; my rain dries all the land it touches. What am I?

A lion and its tamer are standing inside a cage that measures 1 unit in radius. Both of them can effortlessly run at the speed of 1 unit maximum.

1) Suppose the lion is hungry, will he be able to eat up the tamer?
2) If yes, how long can the tamer survive?