There is a creature which could double its size every day. So, if the creature is put in a tank then it will fill the tank in 10 days.
How many days would it take for the creature to fill 1/2 and 1/4 of the tank?
9 days to fill 1/2 and 8 days to fill 1/4 of the tank. If the creature fills the tank in 10 days and it doubles every day, on the ninth day it would fill 1/2 the tank. Thus on the 8th day it will fill 1/4 of tank.
There are 4 borthers 3 of them want to buy a television which is 30 pounds. Each of them pay 10 pound each they give the money to the fourth brother and asked him to go into town and buy the television. When he got there the man said there was 5 pounds off so the fourth brother took the 5 pound and television and left. He decided to make some money out of this so he took 2 pounds and give the other 3 pounds to his brothers. So the 3 brothers only payed 9 pounds each. 3 times 9 is 27 were is the last pound?