What is the difference between a jeweller and a jailer?

A red house is made out of red bricks. A yellow house is made out of yellow bricks. And, a blue house is made out of blue bricks. So, what is a greenhouse made of?

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?

I cannot talk, but I always reply when spoken to. What am I?

Prove that twice of ten is the same as twice of eleven.

A bank customer had $100 in his account. He then made 6 withdrawals. He kept a record of these withdrawals, and the balance remaining in the account, as follows:

Withdrawals Balance left
$50 $50
$25 $25
$10 $15
$8 $7
$5 $2
$2 $0
----- -----
$100 $99

Why are the Totals not tallying?

What has a ring but no finger?

Buy me, smell me or deliver me, I do not change.

Who am I?

When can we add 2 to 11 and get 1 as the correct answer?

Which Travels Faster? Solve below famous picture riddle: