Which is the rope you never skip with?

In 1990, a person is 15 years old. In 1995, that same person is 10 years old. How can this be?

What demands an answer, but asks no questions

Which three-digit number, made of consecutive digits, like 567, is 2 less than a cube and 2 more than a square?

Given that

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

Can you find out

(99)^2 =?

(Note: This is Logical, not Mathematical)

Four men were in a boat on the lake. The boat turns over, and all four men sink to the bottom of the lake, yet not a single man got wet! Why?

Find three whole, positive numbers that have the same answer when multiplied together as when added together.

Speaking of rivers, a man calls his dog from the opposite side of the river. The dog crosses the river without getting wet, and without using a bridge or boat. How?

I have one of the three numbers: 1, 2, or 3 in my mind. I speak only truth. You can ask me just one question for which I will only reply in yes or no or don't know. What question will you ask from me so that you are able to know the number?

Can you name any English verb that becomes its past tense by simply rearranging the alphabets ?