How many words can a pen with half refill write?

Two friends decide to get together; so they start riding bikes towards each other. They plan to meet halfway. Each is riding at 6 MPH. They live 36 miles apart. One of them has a pet carrier pigeon and it starts flying the instant the friends start traveling. The pigeon flies back and forth at 18 MPH between the 2 friends until the friends meet.

How many miles does the pigeon travel?

Can you decipher the below rebus?

PBLUESAISNUERSES

I am white when I am dirty, and black when I am clean. What am I?

Can you count the number of quadrilaterals in the picture below?

The product of three consecutive numbers is 7980.
Then the sum of these consecutive numbers would be?

Three brothers Jacob, John, and James live in Mexico City. The product of the ages of these brothers is 175. Jacob and John are twins. How old is James?

Can you think of a smallest +ve number such that if we shuffle the digits of the number, the new number becomes double the original number?

I am lying and I always lie. Tell me whether I am lying or telling the truth.

Can you convert the number zero(0) into a positive number using just one mathematical operator ?