Three planks of different lengths, V, W and X are nailed together to make a frame as shown. Plank V has 3 holes which divide it into 4 equal parts. Plank W has 4 holes which divide it into 5 equal parts and Plank X has 5 holes which divide it into 6 equal parts. In the frame, the holes Q, R and S are three corners of an equilateral triangle. Plank V is 240 cm long. What is the total length of Plank V, Plank W and Plank X?
Length of Plank V = 240 cm

Length of each interval of Plank V
= 240 ÷ 4
= 60 cm

Length of 2 intervals of Plank V
= 2 x 60
= 120 cm

Length of each interval of Plank W 
= 120 ÷ 3
= 40 cm

Length of Plank W
= 5 x 40
= 200 cm

Length of each interval of Plank X
= 120 ÷ 4
= 30 cm

Length of Plank X
= 6 x 30
= 180 cm

Total length of Plank V, Plank W and Plank X
= 240 + 200 + 180
= 620 cm

Answer(s): 620 cm