Question bank/NEET UG/Physics
NEET UGPhysicsModerateNEET 2025
Two cities X and Y are connected by a regular bus service with a bus leaving in either direction every T min. A girl is driving scooty with a speed of 60 km/h in the direction X to Y notices that a bus goes past her every 30 minutes in the direction of her motion, and every 10 minutes in the opposite direction. Choose the correct option for the period T of the bus service and the speed (assumed constant) of the buses.
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Sol.
<image_1>
X → Y
Let velocity of bus = v km/hr
Relative velocity of bus w.r.t. scooty = (v − 60)
Distance between 2 consecutive buses = vT
(v − 60)30 = vT ...(i)
Y → X
(v + 60)10 = vT ...(ii)
Equating (1) and (2)
(v − 60)30 = (v + 60)10
∴ v = 120 km/hr
T = 15 min
<image_1>
X → Y
Let velocity of bus = v km/hr
Relative velocity of bus w.r.t. scooty = (v − 60)
Distance between 2 consecutive buses = vT
(v − 60)30 = vT ...(i)
Y → X
(v + 60)10 = vT ...(ii)
Equating (1) and (2)
(v − 60)30 = (v + 60)10
∴ v = 120 km/hr
T = 15 min
Source: geekyrakshit/indian-exam-questions / neet2025-code45
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