Question

A surveyor measured the distance between two points on the plan drawn to a scale 1 cm = 40 m and the result was 468 m. Later however, he discovered that he had used a scale of 1 cm = 20 m. Find the true distance between the two points.
1. 1023 m
2. 451 m
3. 220 m
4. 936 m
5. 810 m

Answer 1

Correct Answer - Option 4 : 936 m

Concept:

Representative Factor = Map distance / ground distance

Corrected length = (R.F of wrong scale/R.F of corrected scale) × Measured length

Calculation:

Given: Original scale, 1 cm = 40 m, Wrong scale, 1 cm = 20 m, and Measured length = 468 m

R.F of wrong scale ⇒ 1 cm → 20 m ⇒ 1/2000

R.F of corrected scale ⇒ 1 cm → 40 m ⇒ 1/4000

Corrected length = ((1/2000)/(1/4000)) × 468 = 936 m.