AFCAT Model Paper 4

GIVEN:
Length of the train = 240 m
FORMULA:
Length of the train = (Time taken to cross a man walking in the same direction) × (Speed of the train - Speed of the man)
CALCULATION:
Let the speed of the train be v km per hour
Speed of train with respect to the walking man =(v−8)×(

5

18

)
⇒

(5v−40)

18

-----(1)
Speed of train with respect to the running man =(v+10)×(

5

18

)
⇒

(5v+50)

18

------(2)
According to the question and from (1)
[240÷{

(5v−40)

18

}]=12
⇒240×18=12×(5v−40)
⇒ v – 8 = 72
⇒ v = 80 km per hour
Now, The required time to cross the running man =

240

{ (5v+50) 18 }

⇒

(240×18)

(5×80+50)

⇒ 9.6 seconds
∴ The required time is 9.6 seconds.