1. The diameter of the driving wheel of a bus is 140 cm. How many revolutions per minute must the wheel make in order to keep a speed of 66kmph?
2. A is twice as good as B and together they finish a piece of work in 18 days. In how many days will A alone finish the work?
3. A farmer built a fence around his 17 cows in a square shaped region. He used 27 fence poles on each side of the square. How many poles did he need altogether?