Which Number is the odd one out?

A) 7145
B) 2716
C) 5321
D) 4135

How many triangles are there on the puzzle below?

I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

Three doctors said that Bill was their brother. Bill says he has no brothers. How many brothers does Bill actually have?

Astrology starts with the alphabet A, Biology starts with B, Psychology with P and Limnology with L.

Can you find an "ology" that begins with a P?

A man is sitting in a bar when a rich man sits next to him. He turns to the rich man and says, “Did you know I know almost every song that has ever existed?”

The rich man laughs. The man then says, “I bet you all the money you have in your wallet that I can sing a genuine song with a lady’s name of your choice in it. The rich man laughs again and says, “OK, how about my daughter’s name, Jamie Armstrong-Miller?” Minutes later, the man collects his cash and the rich man goes home cashless. What song did the man sing?

I speak without a mouth, and hear without ears. I have no-body, but I come alive with the wind. What am I?

What is more useful when it is broken?

A wealthy man lives alone in a small cottage. Being partially handicapped he had everything delivered to his cottage. The mailman was delivering a letter one Thursday when he noticed that the front door was ajar. Through the opening he could see the man's body lying in a pool of dried blood. When a police officer arrived he surveyed the scene. On the porch were two bottles of warm milk, Monday's newspaper, a catalog, flyers, and unopened mail. The police officer suspects it was foul play. Who does he suspect and why?

In 1990, a person is 15 years old. In 1995, that same person is 10 years old. How can this be?