Why is a river so rich ?

I sleep during the day and fly at night, but I have no feathers to aid my flight. What am I?

Given that

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

Can you find out

(99)^2 =?

(Note: This is Logical, not Mathematical)

What does an Island and the letter T have in common?

What mathematical symbol can be put between 5 and 9, to get a number bigger than 5 and smaller than 9?

If one and a half boys, eat one and a half burgers in one and a half hours.

How many burgers can 9 boys eat in 3 hours?

Find the missing letter in the last circle logically in the given below picture.

Use the numbers 2, 3, 4 and 5 and the symbols + and = to make a true equation. Conditions: Each must be used exactly once and no other numbers or symbols can be used.

What does this Rebus Picture means ?

What is the four-digit number in which the first digit is one-third the second, the third is the sum of the first two, and the last is three times the second?