Riddles of what is cut on a table but never eaten

Mary is 3 years old, David is twice her age, when David will have 60
how old Mary will have?

Answer

57

You have five pieces of chain, each consisting of three links. You want to make one long chain of these five pieces. Breaking open a link costs 1 euro, and welding an open link costs 3 euros.
Is it possible to make one long chain of the five pieces, if you have just 15 euros?

Answer

Yes, this is possible. First, break open all three links of one of the pieces of chain. This costs 3×1 = 3 euros. Then join the remaining four pieces of chain with the three open links. Welding these links costs 3×3 = 9 euros. The total costs are 12 euros.

A truck driver went down a one - way street the wrong way. There were two traffic police present , yet,they did not fine him. How come?

Answer

Because he is walking

I was a hot Sunday afternoon and a woman was walking slowly through the savanna when she spotted a ferocious tiger in the distance. Instead of turning around or seeking refuge, the woman began to run towards the tiger.
Why didn't she run away?

Answer

The woman was at the zoo.

A man is found dead in the middle of the desert. Next to him lies an unopened package. He had food and water to survive the trip. However what was in the package explains his death.
What was in the package?

Answer

The man was jumping out of a plane and his parachute didn't deploy.

Two legs I have, and this will confound, only at rest do they touch the ground.
What am I?

Answer

Wheelbarrow.