Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

A large water tank has two inlet pipes (a large one and a small one) and one outlet pipe. It takes 3 hours to fill the tank with the large inlet pipe. On the other hand, it takes 6 hours to fill the tank with the small inlet pipe. The outlet pipe allows the full tank to be emptied in 9 hours.

What fraction of the tank (initially empty) will be filled in 0.64 hours if all three pipes are in operation? Give your answer to two decimal places (e.g., 0.25, 0.5, or 0.75).

A boy and a girl are sitting on the porch.
"I'm a boy," says the child with black hair.
"I'm a girl," says the child with red hair.
If at least one of them is lying, who is which?

Find The Next Number in the series:

12 13 15 17 111 113 117 119 123 ?

Can you find the largest Three-digit number whose sum is 14 and whose square is less than 5,00,000?

Which digit occurred maximum times between the number 1 and 1000?

Given that

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

Can you find out

(99)^2 =?

(Note: This is Logical, not Mathematical)

The person who makes it has no need for it. He who purchases it does not use it. The person who does use it does not know they are. What is it?

What has hands, but can’t clap?

Which is the correct shadow of the bird?