The first box has two white balls. The second box has two black balls. The third box has a white and a black ball.
Boxes are labeled but all labels are wrong!
You are allowed to open one box, pick one ball at random, see its color and put it back into the box, without seeing the color of the other ball.
How many such operations are necessary to correctly label the boxes?
open the mix container and check!
If it’s black, the white ones are on the black label and the mix is in the white label
If it’s white, the black ones are on the white label and the mix is in the black label
It cannot be a mix under the mix label as all labels are WRONG!
b.There was a blind man. He had four socks in his drawer either black or white. He opened it and took out two socks. Now the probability that it was a pair of white socks is 1/2.
Can you find out the probability that he had taken out a pair of black socks ?
This question can be a tricky one. The probability that is asked will be zero.
If the probability off taking out a pair of white socks is 1/2, it means that there is no black pair. This is because if there had been, there would have been three cases – white pair, black pair and mixed pair. But since in the question it is clear that there were just two chances (1/2), we can fairly deduce that there were only one black sock and the rest were white.
c.A rubber ball keeps on bouncing back to 2/3 of the height from which it is dropped. Can you calculate the fraction of its original height that the ball will bounce after it is dropped and it has bounced four times without any hindrance ?
g.Having an infinite supply of water and two containers, one for 3 liters and one for 5 liters, how would you measure 4 liters?
- Fill and pour 3 liters into the 5 liter container
- Refill 3 liter container, transfer as much as possible to the 5 liter container
- Retain the one liter left in the 3 liter container, empty the 5 liter container
- Transfer the one liter from the 3 liter to the 5 liter container
- Refill the 3 liter and transfer it to the one liter in the 5 liter container…
- that means 3+3-5+3=4