1. Next door to me are 4 brothers of different heights. Their average height is 74 inches and the difference among height of the first three men is 2 inches. The difference between the 3rd and the 4th brother is 6 inches. How tall is each brother?
2. In a family, each son has as many sisters as brothers but each daughter has twice as many brothers as sisters. How many brothers and sisters are there?
3. A train is one mile long. It travels at the rate of 1 mile/minute through a tunnel one mile long. How long will it take for the train to pass completely through the tunnel?
4. A container contains an unknown virus. Every day the virus doubles. On day one there is one virus. On day two there are two viruses. On day three there are four viruses and so on. On the 19th day the container becomes full of viruses. On which day is the container half full?
5. A railway track runs in parallel with a road untill a bend brings the road to a level crossing. A cyclist rides along the road to work every day at 12 miles/hour. He meets the train travelling in the same direction at the level crossing every day. On a particular day he was late by 25 minutes and he met the train six miles ahead of the level crossing. What is the speed of the train?
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