How many points are there on the globe where, by walking one mile south, then one mile east and then one mile north, you would reach the place where you started?
You are mixing a mixture of cement and Sand with five gallons of water. You have a garden hose giving you all the water you need. The problem is that you only have a four-gallon bucket and a seven-gallon bucket and neither has graduation marks. Find a method to measure five gallons.