Question: "The average length of 20 wooden planks is 75 cm. When 4 new planks with lengths x, x+10, x + 20 and x+30 cm are added..." | TestX

Loading Question: "The average length of 20 wooden planks is 75 cm. When 4 new planks with lengths x, x+10, x + 20 and x+30 cm are added..." | TestX...