A thief steals an item and escapes, running at a speed of 15 km/h. A policeman arrives at the spot of the crime after 4 minutes and immediately starts chasing the thief. 16 minutes after the policeman started to chase the thief; there is still a gap of 200 m between the two. At what distance from the spot of the crime will the policeman catch up the thief and what is the speed (in km/h) of the policeman?

Question

Question

This question was previously asked in

SSC CGL 2023 Tier-I Official Paper (Held On: 25 Jul 2023 Shift 4)

Answer 1

Given:

Speed of thief = 15 km/hr

Formula used:

Distance = relative speed × time

Calculation:

Distance covered by thief in 20 minutes = 15 × (20/60) = 5 km

Since there is a gap of 200,m = 5 - 0.2 = 4.8 km.

Distance covered by a policeman in 16 minutes = 4.8 km

⇒ Speed of policeman × (16/60) = 4.8

⇒ Speed of policeman = (4.8 × 60)/16 = 18 km/hr

Now,

Distance = relative speed × time

⇒ 200 = (18 - 15) × (5/18) × time

⇒ Time = (200 × 18)/(3 × 5)

⇒ Time = 240 sec

Distance covered by thief = (15 × 240)/3600 = 1 km

Total distance covered by thief = 5 + 1 = 6 km

∴ The correct option is 2.

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