21. The amount of caffeine in Jan's body goes down by twenty-eight percent every hour. How long, to the nearest hour, until Jan's body has only 28 percent of the caffeine that
was in her original cup?

The perimeter of an equilateral triangle is 4 cm more than the perimeter of a square and the length of a side of the triangle is 8 cm more than the length of a side of the aware. find the length of a side of the equilateral triangle