Fencing a rectangle: The length of a rectangular plot is 20 m more than its breadth. If total fencing cost at Rs 26.50 per metre is Rs 5300, find the length of the plot (in metres).

Introduction / Context:
This is perimeter-from-cost, then dimensions-from-perimeter algebra, concluding with identification of the correct length among options.

Given Data / Assumptions:

• Cost = Rs 5300
• Rate = Rs 26.50 per m
• L = B + 20

Concept / Approach:
Perimeter P = Cost / Rate. For a rectangle, P = 2(L + B). With L = B + 20, solve for B and then L.

Step-by-Step Solution:

Verification / Alternative check:
Perimeter check: 2*(60+40) = 2*100 = 200; Cost check: 200*26.5 = 5300. All consistent.

Why Other Options Are Wrong:
40, 20, 30, 50 are not the computed length; correct length is 60, which is not listed; therefore “none of these”.

Common Pitfalls:
Forgetting to divide perimeter by 2 or misdividing 5300 by 26.5 (it equals 200 exactly).

Final Answer:
none of these