Water jar puzzle

You have three jars that hold max 19, 13 and 7 liters of water
respectively. 13 and 7 litre jars are full of water and 19 litre jar
is empty (so total 20 litres of water).

You can pour water between jars and I want two jars with 10
litres of water (ie 10, 10, 0 from 0, 13, 7)

Unlock the Safe

There is a safe with a 5 digit number as the key. The 4th
digit is 4 greater than the second digit, while the 3rd digit
is 3 less than the 2nd digit. The 1st digit is thrice the
last digit. There are 3 pairs in the number whose sum is 11.

Find the number.

3x3x3 wooden cube

Imagine a 3x3x3 wooden cube.

How many cuts do we need to break it into 27 1x1x1 cubes?

Crossing the river

Two boys want to cross a river. The only way to get to the other
side is by boat, but that boat can only take one boy at a time.
The boat cannot return on its own, there are no ropes or similar
tricks, yet both boys manage to cross the river using the boat.

How they manage to cross?

Five Pirates

5 pirates of different ages have a treasure of 100 gold coins.

On their ship, they decide to split the coins using this scheme:

The oldest pirate proposes how to share the coins, and all pirates
remaining will vote for or against it.

If 50% or more of the pirates vote for it, then the coins will be shared
that way. Otherwise, the pirate proposing the scheme will be thrown
overboard, and the process is repeated with the pirates that remain.

Assuming that all 5 pirates are intelligent, rational, greedy,
and do not wish to die, (and are rather good at math for pirates)
what will happen?

Anil & Mail

Anil has to receive a mail from Station, but the train arrives
early and the mail is then sent by a cart to him. Both Anil and
cart met in the middle in 30 mins. Due to this in whole journey
anil saved 20 mins, due to eary arrival of train.

Now tell me how early the train arrived?

Profit Maximization

A manufacturer can sell X items (X >= 0) at a price of Rs. (330 - X)
each. The cost of producing X items is ((X^2) + 10X + 12).
Determine the no. of items sold so that the manufacturer can make
the maximum profit..