What occurs twice in a week, once in a year but never in a day?

Assume there are approximately 5,000,000,000 (5 billion) people on Earth. What would you estimate to be the result, if you multiply together the number of fingers on every person's left hand? (For the purposes of this exercise, thumbs count as fingers, for five fingers per hand.) If you cannot estimate the number then try to guess how long the number would be.

Can you circle exactly four of these numbers such that the total is twelve?

1 6 1
6 1 6
1 6 1
6 1 6

1 + 9 + 8 = ?
considering, 28 + 8 + 92 = 10

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?

A Monkey, a squirrel, and an Eagle are racing to the top of the mango tree. Assuming all these animals are in perfect shape, Which animal will reach to Banana first?

How many bricks does it take to complete a building that is 15 feet wide, 30 feet deep, and 12 feet tall made of brick?

If all Goats are Sheep and all Sheep are Deers, are all Deers Goats ?

What mathematical symbol can be put between 5 and 9, to get a number bigger than 5 and smaller than 9?

"That Restaurant always remains crowded. This is the reason why nobody goes there".

Can you find a flaw in this statement?