Questions

- Send the box with the lock to Alex. 

- Alex can't open it, but can put another lock on the box. 

- Alex sends this box with the 2 locks back to you, you unlock your lock and send it back to Alex again.

- So there is just Alex's lock on the box and Alex can now open it.

To display the items in the active list.

1. Pinaka is a multi barrel rocket launcher developed by the Defence Research and Development Organisation (DRDO) for the Indian Army.

2. The system has a maximum range of 40 km for Mark-I and 75 km for Mark-II, and can fire a salvo of 12 rockets in 44 seconds.

3. The system is mounted on a Tatra truck for mobility.

4. Actually, the meaning of Pinaka is Shiv Dhanush.

Our solution:

Toss the coin twice.
Let TH, HT and TT correspond to the three choices.
And if you get HH, just repeat (so it takes 8/3 tosses on average).


BIASED COIN

If the coin was biased, TH and HT would occur with equal probability.
So you could assign THHT, HTTH and THTH to the three choices, with other 4-toss outcomes rejected.
Or you could assign HTT, THT and TTH to the three choices, with other 3-toss outcomes rejected.

Looking at the diagram in  rows, the central circle equals half the sum of the numbers in the other circles to the left and right of the centre.

Computer is the correct word.