2
30. A thief who has escaped at 4:00 am at the rate of 4
miles an hour was followed by a policemen who
started at 7:00 a.m. at the rate of 6 miles an hour. At
what will the policemen catch thief?
B. 12 pm
C. 11 am
D.1
pm
A 2 pm
Answers
Answer:
MATHS
A thief escaped from police custody. Since he was sprinter he could clock 40 km/hr. The police realized it after 3 hr and started chasing him in the same direction at 50 km/hr. The police had a dog which could run at 60 km/hr. The dog could run to the thief and then return to the police and then would turn back towards the thief. If kept on doing so till the police caught the thief. Find the total distance travelled by the dog in the direction of the thief.
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ANSWER
Speed of thief =40 km per hr=v
t
Speed of police =50 km per hr=v
p
Police started after 3hrs of start of thief
50t=40t+40(3)
∴t=12hr
Time taken by police to catch thief =12hr
Distance travelled by dog =12×60
=720km
⇒ Distance travelled by police + To and from distance by Dog =720
Distance travelled by police =50×12
=600km
⇒ 600+2(from distance by dog)=720
"Fro" distance (distance from thief to police)="to"distance(distance from police to thief after once it returns)
600+2(’fro’ distance by dog)=720
∴ 'fro' distance =60
∴ Total distance towards thief =600+
′
to" distance
=720− 'fro' distance
=660km
Answer:
C. 11 am
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