I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

If I remove one from eleven it becomes Ten and if I remove one from nine also becomes Ten. How?

John is a strange liar.

He lies on six days of the week, but on the seventh day, he always tells the truth.

He made the following statements on three successive days:

Day 1: "I lie on Monday and Tuesday."
Day 2: "Today, it"s Thursday, Saturday, or Sunday."
Day 3: "I lie on Wednesday and Friday."

On which day does John tell the truth?

A Scientist was fifty years old in the year 2000 but he was forty years old in the year 2010. How can this be possible?

PS: It has a logical answer.

A man and a dog were going down the street. The man rode, yet walked. What was the dog’s name?

Given that

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

Can you find out

(99)^2 =?

(Note: This is Logical, not Mathematical)

Doctor Alex and a bus driver John are both in love with the same woman named Olivia. The bus driver need to go for a long trip of 10 days, Before he left he gave Olivia 10 apples.

How many points are there on the globe where, by walking one mile south, then one mile east and then one mile north, you would reach the place where you started?

What 4-letter word can be written forward, backward or upside down, and can still be read from left to right?

I have a hole in my back and legs I lack.
I live where I can’t breathe and I eat without teeth.
What am I?