Replace the question mark with the correct number.

Krish is 45 years old and his mother Crishtina is 73 years old.

Can you find out how many years ago, his mother was three times his age?

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

I have cities, but no houses. I have mountains, but no trees. I have water, but no fish. What am I?

What does the below rebus riddle means?

You may enter, but you may not come in. I have space, but no room. I have keys, but open no lock. What am I?

As shown in the image, the nine Dogs are square fenced. By constructing just two square fences can you make sure that two Dogs cannot meet each other without crossing the fence?

How can one talk without saying a single word?

When does a USA Potato change its nationality?

John and Jacob are twin brothers. One of them is a liar whereas the other one is a truth-teller.

I called their home number and one of them picked up.
I asked. 'Does John lie?' The person replied with a yes.

Whom did I talk with, John or Jacob?