Time, Speed & Distance
Aptitude

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Q.

A train covers a distance in 50 min, if it runs at a speed of 48 kmph on an average. The speed at which the train must run to reduce the time of journey to 40 min will be.

 A.

45 kmph

 B.

60 kmph

 C.

75 kmph

 D.

None of these

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Solution:
Option(B) is correct

Time = \(\dfrac{50}{60}=\dfrac{5}{6}\) hr

Speed = 48 mph

Distance  = \(S\times T=48\times \dfrac{5}{6}=40\) km

Time = \(\dfrac{40}{60} \) hr

New speed = \(40\times \dfrac{3}{2}=60\) kmph


(5) Comment(s)


Veer
 ()

let me explain in detail using ratio method

given distance traveled is constant then speed indirect variation to time

the ratio of time is 5:4

ratio of speed is 4:5 if 4->48 then 5->?

cross mul then ==60



Rini
 ()

no need of conversion needed?? minute and hour ryt?



Pooja Vishwakarma
 ()

T1/T2 = V2 / V1

5/6 V2

---- = -----

4/6 48

V2 = 60 kmph.


Pooja Vishwakarma
 ()

T1/T2 = V2 / V1

$

5/6 V2

---- = -----

4/6 48

$

V2 = 60 kmph.


Akshay
 ()

no need to find distance simple one liner solution inverse of ratio of speed as time and speed are inverse proportion .So simple 48 *5/4 =60