Logic Riddles

A Marble Hall (medium)

Question: In a marble hall as white as milk, Lined with skin as soft as silk, Within a fountain crystal clear, A golden orb does appear, There are no doors to this stronghold, Yet thieves break in and steal the gold. What am I?

The 6 sisters (medium)

Question: There are 6 sisters. Each sister has 1 brother. How many brothers are in the sisters' family?

School (medium)

Question: Nathan has math 4 times a week. If he has math 8:00 Monday, 9:20 on Tuesday, 10:40 on Wednesday, and 1:20 on Friday, when does Nathan have math on Thursday?

By Bist

Question: Having one, means having something to follow. Once you question it, it means having none. People seek it, but some do and some don't find it. What is it?

By Bist

Question: Having some, you want more. But when you have too much of it you feel bored. Everyone people wants it, and some have to much of it. What is it?