By removing one matchstick and adding one matchstick, can you convert the word "ZOO" to an animal name?

I went to the bookshop and spent one-half of the money that was in my purse.

When I came out, I found that I had as many cents as I had dollars and half as many dollars as I had cents when I went in. Find the money in my purse when I entered the store.

If,

20 % 5 = 24

21 % 7 = 33

42 % 6 = 67

Then;

66 % 6 = ?

What is the longest word in the dictionary?

A man has a barrel filled with oil that weighs 100 pounds, and then he puts something into it. Now the barrel weighs less than 100 pounds. What did he put in the barrel?

Solve the puzzle by telling what does below picture means.

Count the number of triangles in the picture below:

Can you count the number of seconds in a year?

Clue: You need to bother about calculation.

Solve the following series:
AZ, GT, MN, __, YB

Find the 8 in the below-given Image.