If,
29 - 1 = 30
9 - 1 = 10
14 - 1 = 15

Based on similar logic, Can you prove that the below algebraic equation is true?
11 - 1 = 10 ?

A bridge is about to collapse. There are four people P, Q, R and S on one of the sides. Before the bridge collapses, they want to cross it. Now since the bridge is too weak, it can only stand the weight of two people at a time. Also, it is night time and nothing is visible. They have just one torch with them.

Now P takes one minute to cross the bridge, Q takes two minutes to cross, R takes five minutes to cross and S takes ten minutes to cross.

The bridge will collapse in seventeen minutes. How will they be able to cross the bridge before it collapses?

You enter your friend's room. He is not in his room. Although you see that on the bed there are two dogs, five cats, two giraffes and three pigs. Also, a couple of chickens and ducks are flying in the room.

Calculate the number of legs standing on the floor.

I am weightless, but you can see me. Put me in a bucket, and I'll make it lighter. What am I?

Two boys wish to cross a river. The only way to get to the other side is by boat, but that boat can only take one boy at a time. The boat cannot return on its own, there are no ropes or similar tricks, yet both boys manage to cross using the boat.

How?

A Miser man decided to go on a vacation for a month. He goes to the bank and asks for a trip loan of $500. The bank officer asks the man that the loan can only be approved when he mortgage some valuable thing at the bank. Miser man mortgages his only car whose worth was a whopping $80000. The Bank officer laughed at him and approve the loan instantly. After vacation when the miser man returns, the bank officer asked him "Are you an idiot, why is your mortgage such an expensive car for such a short loan?".

Miser man replied with some reason and the bank officer agreed that the miser man is actually not an idiot.

What did miser man reply to the bank loan officer?.

What month of the year has 28 days?

There were five men at church, and it started raining while they were outside. The four that ran still got wet, but the one that was still stayed completely dry. Why did he stay dry?

Can you find out what is missing?

1 3 5
2 4 ?

Hint: It's not six. Think out of the box.

Can you decipher the two rows to find the hidden word?