Difficulty: Medium
Correct Answer: 153,600 m²
Explanation:
Problem restatement
From speed and time, get the perimeter, then use the 3:2 ratio to find actual sides and hence the area.
Given data
Concept/Approach
Distance = speed × time ⇒ P. With 2(L + B) = P and L:B = 3:2, solve for L and B, then area = L × B.
Step-by-Step calculation
P = 12 × (2/15) = 24/15 = 8/5 km = 1.6 km = 1600 mLet L = 3x, B = 2x ⇒ 2(L + B) = 2(5x) = 10x = 1600 ⇒ x = 160L = 480 m, B = 320 mArea = 480 × 320 = 153,600 m²
Verification/Alternative
Perimeter from sides: 2(480 + 320) = 2 × 800 = 1600 m, matching the lap distance.
Common pitfalls
Forgetting to convert km to meters and minutes to hours before multiplying.
Final Answer
153,600 m²
Discussion & Comments