The length of a plank is 3 m 3 cm long. Kathy cut the plank into 3 pieces. The length of the first piece of the plank is 77 cm. The length of the second piece of the plank is 2 m shorter than the third piece. What is the length of the third piece of plank?
1 m = 100 cm

Difference in the length between the second and the third piece
= 2 m
= 2 x 100
= 200 cm

Length of a plank
= 3 m 3 cm
= 3 x 100 + 3
= 303 cm

Length of the first piece = 77 cm
Length of the second piece = 1 u
Length of the third piece = 1 u + 200 cm

1 u + 1 u + 200 + 77 = 303
2 u + 277 = 303
2 u = 303 - 277 = 26
1 u = 26 ÷ 2 = 13 

Length of the third piece of plank
= 1 u + 200
= 13 + 200
= 213 cm

Answer(s): 213 cm