Anju's journey comprises three segments. He travels the first 'd - 30' km at a speed of 12 km/h, the next 'd' km at a speed of 30 km/h, and finally, she covers the remaining 'd + 30' km at a speed of 24 km/h. The question requires determining the value of 'd' given that her average speed for the entire journey is 20 km/h.