You have a roll of cloth 1km long. You have a machine which cuts this roll into pieces of 10-meter-long cloth.

How long would it take for the machine to cut the roll if each cut took 4 secs?

I am the black child of a white father, a wingless bird, flying even to the clouds of heaven. I give birth to tears of mourning in pupils that meet me, even though there is no cause for grief, and at once on my birth, I am dissolved into air. What am I?

The product of three consecutive numbers is 7980.
Then the sum of these consecutive numbers would be?

A famous swimmer can swim downstream in a lake in exactly 40 minutes with the lake current.
He can swim upstream in that lake in exactly 60 minutes against the lake current.
The length of the lake is 2 km.

How long he can cover the distance of one side at a still lake with no current?

A doctor and a boy were fishing. The boy was the doctor’s son, but the doctor was not the boy’s father. Who was the doctor?

Who always enjoys poor health?

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

You bought me for dinner but never eat me. What am I?

A sundial has the fewest moving parts of any timepiece. Which has the most?

What makes this number unique: 8,549,176,320?