A 30 m chain was found to be 20 cm long after chaining 1500 m. The correct length of the total distance chained will be
- A1495 m
- B1500 m
- C1505 m
- D1510 mCorrect
Solution
Concept
Correction for incorrect length of chain
Formula
True length = measured length × (L′ / L)
Step-by-step solution
1. Chain is 20 cm too long, so actual length L′ = 30.20 m; nominal length L = 30 m. 2. True distance = 1500 × (30.20 / 30) = 1510 m.
Explanation
A chain that is too long measures a distance shorter than the true length (it covers more ground per chain length). So the true distance is more than the recorded one: 1500 × 30.2/30 = 1510 m.
Shortcut
True length = measured × (actual chain length ÷ nominal length). Chain too long → true distance is more.
Common mistake
Subtracting the error because the chain is "wrong".
Correct answer: D) 1510 m