A helicopter drops two trains, each on a parachute, onto a
straight infinite railway line. There is an undefined
distance between the two trains. Each faces the same
direction, and upon landing, the parachute attached to each
train falls to the ground next to the train and detaches.
Each train has a microchip that controls its motion. The
chips are identical. There is no way for the trains to know
where they are. You need to write the code in the chip to
make the trains bump into each other. Each line of code
takes a single clock cycle to execute.
You can use the following commands (and only these);
MF - moves the train forward
MB - moves the train backward
IF (P) - conditional that's satisfied if the train is next
to a parachute. There is no "then" to this IF statement.
There are four dogs/ants/people at four corners of a square
of unit distance. At the same instant all of them start
running with unit speed towards the person on their
clockwise direction and will always run towards that target.
How long does it take for them to meet and where?
You have 5 jars of pills. Each pill weighs 10 gram, except
for contaminated pills contained in one jar, where each pill
weighs 9 gm. Given a scale, how could you tell which jar had
the contaminated pills in just one measurement?
Imagine you are standing in front of a mirror, facing it.
Raise your left hand. Raise your right hand. Look at your
reflection. When you raise your left hand your reflection
raises what appears to be his right hand. But when you tilt
your head up, your reflection does too, and does not appear
to tilt his/her head down. Why is it that the mirror appears
to reverse left and right, but not up and down?
You have two jars, 50 red marbles and 50 blue marbles. A jar
will be picked at random, and then a marble will be picked
from the jar. Placing all of the marbles in the jars, how
can you maximize the chances of a red marble being picked?
What are the exact odds of getting a red marble using your
One train leaves Los Angeles at 15mph heading for New York.
Another train leaves from New York at 20mph heading for Los
Angeles on the same track. If a bird, flying at 25mph,
leaves from Los Angeles at the same time as the train and
flies back and forth between the two trains until they
collide, how far will the bird have traveled?
You've got someone working for you for seven days and a gold
bar to pay them. The gold bar is segmented into seven
connected pieces. You must give them a piece of gold at the
end of every day. If you are only allowed to make two breaks
in the gold bar, how do you pay your worker?
There are 3 baskets. one of them have apples, one has
oranges only and the other has mixture of apples and
oranges. The labels on their baskets always lie. (i.e. if
the label says oranges, you are sure that it doesn't have
oranges only,it could be a mixture) The task is to pick one
basket and pick only one fruit from it and then correctly
label all the three baskets.
There Are 3 Fruit Baskets - One Labelled As Apples Another As Oranges And The Third As Mixture Of Apples And Oranges. The Labels On The Baskets Always Lie. The Task Is To Pick One Basket And Pick Only One Fruit From It And Then Correctly Label All