Using four sevens (7) and a one (1) create the number 100. Except for the five numerals, you can use the usual mathematical operations (+, -, x, :), root and brackets ()
You walk into a creepy house by yourself. There is no electricity, plumbing, or ventilation. Inside you notice 3 doors with numbers on them. Once you open the doors you will die a particular way. Door No.1 You’ll be eaten by a lion who is hungry. Door No.2 You’ll be stabbed to death. Door No.3 There is an electric chair waiting for you. Which door do you pick?
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?