What happened when the wheel was invented?

Two girls were born to the same mother, on the same day, at the same time, in the same month and year and yet they're not twins. How can this be ?

A patient was diagnosed with some ailment. He was given five different tablets to take at night at an interval of 15 minutes.

How long will it take the patient to consume all the five tablets?

In the image below, can you find the value of an angle(y)

Replace the question mark with the number below given a simple math problem.

Luis Garavito killed Density x Volume.

Who is Luis Garavito ?

Count the number of times the letter "F" appears in the following paragraph:

FAY FRIED FIFTY POUNDS OF
SALTED FISH AND THREE POUNDS
OF DRY FENNEL FOR DINNER FOR
FORTY MEMBERS OF HER FATHER'S FAMILY.

My friends called me Iron59 because my parents are a chemist and a mathematician. What is my real name?

What goes up but never comes down?

Below the four parts have been reorganised. The four partitions are exactly the same in both arrangements. Why is there a hole?