Level 3
Three planks of different lengths, X,Y and Z are nailed together to make a frame as shown. Plank X has 3 holes which divide it into 4 equal parts. Plank Y has 4 holes which divide it into 5 equal parts and Plank Z has 5 holes which divide it into 6 equal parts. In the frame, the holes A, B and C are three corners of an equilateral triangle. Plank X is 120 cm long. What is the total length of Plank X, Plank Y and Plank Z?