Lawn 120 m × 60 m with 1.5 m inner border all around:\nA rectangular grassy plot 120 m by 60 m has a 1.5 m wide gravel path running all round on the inside. Find the cost of gravelling this path at Rs 0.65 per sq m.

Introduction / Context:
Border (annulus-like) area equals outer rectangle minus the inner clear rectangle after shrinking each side by twice the border width.

Given Data / Assumptions:

• Outer: 120 m × 60 m.
• Border width w = 1.5 m.
• Rate = Rs 0.65 per sq m.

Concept / Approach:
Inner dimensions = (120 − 2w) × (60 − 2w) = 117 × 57. Area(path) = 120×60 − 117×57.

Step-by-Step Solution:

Verification / Alternative check:
Difference-of-areas method is standard for uniform borders.

Why Other Options Are Wrong:
They correspond to incorrect inner dimensions or rate multiplication.

Common Pitfalls:
Subtracting only once the width instead of twice (both sides).

Final Answer:
Rs. 345.15.