Can you make four (4) nines (9) equal 100?

A Club organizes a Running Race, and John, Jacob, Minda, and Tony participated.

The results are as follows

John beats Jacob
Minda beats Toni
Toni beats John

Who came first in the race?

When my father was 31 I was 8. Now he is twice as old as me. How old am I?

In a supermarket, there is an intelligent glass pane before a refrigerating unit. This glass pane allows cherries and apples through it but does not allow grapes and Orange to pass through it.

Can you identify the rule that the glass pane is following?

Eight of us go fourth, not back, to protect our king from an attack. What are we?

A sundial has the fewest moving parts of any timepiece. Which has the most?

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

There is a box full of marbles,
all but two are blue,
all but two are green,
and all but two are red.

How many marbles are in the box?

What is a word made up of 4 letters, yet is also made up of 3. Sometimes is written with 9 letters, and then with 4. Rarely consists of 6, and never is written with 5.

The square root of number 121 is "11". What is the square root of the number "12345678987654321."?