A train speeds past a pole in 10seconds and a platform 50 m long in 20 seconds. Its length is:
Select the correct option
A) 30 m.
B) 40 m.
C) 60 m.
D) 50 m.
E) 70 m.
Let the length of the train be x meters and its speed be y m/sec.   They, x / y = 10 =&gt; y = x/10   x + 50 / 20 = x / 10   x = 50 m.   Answer: Option 50 m.
<result>D</result>
A train speeds past a pole in 10seconds and a platform 50 m long in 20 seconds. Its length is: