Earth spread over remainder of field — compute level rise (corrected spread area): A rectangular pit (tank) measuring 5 m × 4.5 m × 2.1 m is dug at the center of a rectangular field measuring 13.5 m × 25 m. The dug earth is spread evenly over the remaining portion of the field (excluding the pit area). By how much (in meters) is the level of the field raised?

Introduction / Context:
Here the earth from the pit is not spread over the entire field but only over the remaining part after excluding the pit footprint. This slightly increases the rise compared to spreading over the whole field.

Given Data / Assumptions:

• Pit volume V = 5 * 4.5 * 2.1 m3
• Field area A_field = 13.5 * 25 m2
• Pit base area A_pit = 5 * 4.5 m2
• Spread area A_spread = A_field − A_pit

Concept / Approach:
Level rise h = V / A_spread.

Step-by-Step Solution:
V = 47.25 m3A_field = 337.5 m2; A_pit = 22.5 m2A_spread = 337.5 − 22.5 = 315 m2h = 47.25 / 315 = 0.15 m

Verification / Alternative check:
If instead spread over the whole field, rise would be 47.25/337.5 = 0.14 m (smaller), confirming exclusion of the pit increases h slightly.

Why Other Options Are Wrong:
0.12 m and 0.18–0.20 m correspond to different spread areas or rounding beyond the given data.

Common Pitfalls:
Forgetting to exclude the pit base area from the spread area.

Final Answer:
0.15 m