Two buses start from the same depot. Bus A goes 27 km West, then turns to its…
2024
Two buses start from the same depot. Bus A goes 27 km West, then turns to its right and goes 43 km. In the meanwhile Bus B goes 19 km North, then turns West and goes 61 km, then turns to its right and goes 24 km. Where is Bus B with respect to Bus A?
- A.
34 km East
- B.
88 km West
- C.
88 km East
- D.
34 km West
Show answer & explanation
Correct answer: D
Concept: In a direction-sense problem, place the common starting point at the origin of an East-West / North-South coordinate system, with East and North as the positive axes. Track each moving object leg by leg, using the rule that a right turn rotates the current facing direction 90° clockwise (North → East → South → West → North). The relative position of one object with respect to another is then simply the difference between their final coordinates.
Application:
Take the depot as the origin (0, 0) for both buses, with East and North as the positive directions.
Bus A moves 27 km West: its position becomes 27 km West, 0 km North.
Bus A turns right — facing West, a right turn points it North — and moves 43 km: its position becomes 27 km West, 43 km North.
Bus B moves 19 km North: its position becomes 0 km West, 19 km North.
Bus B turns and moves 61 km West: its position becomes 61 km West, 19 km North.
Bus B turns right — facing West, a right turn points it North — and moves 24 km: its position becomes 61 km West, 19 + 24 = 43 km North.
Cross-check: comparing the two buses' final coordinates:
Bus | East-West position (from depot) | North-South position (from depot) |
|---|---|---|
Bus A | 27 km West | 43 km North |
Bus B | 61 km West | 43 km North |
Both buses sit exactly 43 km North of the depot, so they lie on the same east-west line — the entire separation between them is therefore horizontal. Bus B's westward leg (61 km) exceeds Bus A's westward leg (27 km) by 34 km, so Bus B lies 34 km further west than Bus A.
Hence, Bus B is 34 km West of Bus A.