What do you answer even though it never asks you questions?

Find the next number in the series below.

6 18 270 72090 ?

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 find a five letter word that is left with only two letters if one is removed?

There is a shop where written:
Buy 1 for $1
10 for $2
100 for $3
I needed 999 and still only paid $3. How could this be financially viable for the shop-keeper?

You have two bottles of pills marked with labels A and B. The pills are identical. The doctor has asked you to take one A pill and one B pill daily. You cant take more or less than that.

While taking out the pills one day, you took out one pill from A and by mistake took out two from B. You have no idea which pill is which now.

You cant throw away the expensive pills. What will you do now?

Railroad Crossing, look out for the cars. Can you spell that, without any R's ?

Which English verb becomes past tense just by rearranging the letters?

One of the leprechaun is missing if you see the two pictures attached to this question. Where did he go? When he comes back, do you know where has he been?

You have a 12 liters jug full of water. You have two empty 8 liters and 5 liters jug. How can you divide the water into two equal parts using these jugs?