Question

a train takes 65 sec to pass through a tunnel that is990m long it take another 35 sec ti cross a bridge that is 630m long what is the speed of train​

Answer 1

Answer: 12 m/sec

Step-by-step explanation:

Let the Train Length = L m  && Speed = S m/sec

990 m long tunnel:

D = S * T

990 + L = S * 65 ..... (i)

630 m long bridge:

D = S*T

630 + L = S*35 .... (ii)

eq.(i) - eq.(ii)

990+L - 630-L = S*65 - S*35

360 = 30*S

S = 360/30 = 12 m/sec

Speed of train = 12 m/sec

ALTERNATE:

S = D/T

Find the difference of given lengths and time difference

S = 990-630/65-35 = 360/30 = 12 m/s