In a 1000 m race, A beats B by 100 m and C by 200 m. By how much does B beat C in a 1350 m race?
-
A125 m
-
B130 m
-
C140 m
-
D150 m
-
ENone of these
Answer
Correct Answer: 150 m
Explanation
Introduction / Context:When margins versus a common competitor are known, convert them to speed ratios, then compare the two remaining competitors over a new distance by scaling with those ratios.
Given Data / Assumptions:
- When A runs 1000 m, B runs 900 m, and C runs 800 m.
- Speeds are proportional to these distances over equal time: A:B:C = 1000:900:800 = 10:9:8.
- We compare B and C over 1350 m.
Concept / Approach:For equal times, distance ∝ speed. When B finishes 1350 m, C covers (speed_C/speed_B) times that distance.
Step-by-Step Solution: speed_B : speed_C = 9 : 8 C's distance when B finishes = 1350 * (8/9) = 1200 m Lead of B over C = 1350 − 1200 = 150 m
Verification / Alternative check:Consistent with the 10:9:8 baseline; margins scale linearly with course length for uniform speeds.
Why Other Options Are Wrong:125, 130, 140 m are not the exact scaled difference implied by the 9:8 speed ratio over 1350 m.
Common Pitfalls:Using 100 m vs 200 m differences directly without forming ratios; forgetting to scale the margin for the new race length.
Final Answer:150 m