Can anyone tell me a word in the English dictionary which has a silent 'z'?

What is the next number in this series?

4,12,84,3612....

A pack of cards has 40 cards. You are blindfolded. Out of 40, 25 cards are facing down while 15 are facing up. You have been asked to divide this pack of cards into two decks - so that each deck contains an equal number of face-up cards. Remember, you are blindfolded.

How will you do it?

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?

What kind of tree can you carry in your hand?

Find the value of "?" in the ball picture Riddle below:

Find the smallest sentence with all the English alphabet.

Solve the equation by replacing the alphabet with numbers.

MOM + MOM + NO = BOOK=

When you say goodbye, I am what you need to tie.
I come as a couple and go wherever you run.
Who am I?

What number comes next in the series?

5 15 5 18 5 24 14 20 _