What does this below rebus puzzle mean?

What does a man do only once in his lifetime, but women do once a year after they are 29?

Luis Garavito killed Density x Volume.

Who is Luis Garavito ?

The two towns are exactly 100 km apart. John leaves City A driving at 30 km/hr and Jacob leaves City B half an hour later driving at 60 km/hr. Who will be closer to City A when they meet?

Can you count the number of triangles in the given figure?

On her drawing table, Sayna lit 12 coloured candles. A few seconds later she blew two candles off.

How many candles Sayna have at the end?

Solve below rebus puzzle?

I’m light as a feather, yet the strongest person can’t hold me for five minutes. What am I?

Make the seating arrangement of 10 children in such a way that there are 5 rows with 4 children in each row.

It is always ahead of me yet I can never see it. What is it?