A rod was cut into three pieces. The lengths of the three pieces are in the ratio 5:3:2. If the shortest is 25cm long, how long was the rod?

Show workings bit by bit

Let x = length of the rod

5:3:2 = 5x:3x:2x

25cm = 2x

2x/2 = x

25cm/2 = x

x = 12.5cm

Therefore, the rod was 12.5cm long.