What is the four-digit number in which the first digit is one-third the second, the third is the sum of the first two, and the last is three times the second?
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.