A train speeds past a pole in 15 sec and a platform 100 m long in 25 sec, its length is? Select:
A) 298 m
B) 279 m
C) 827 m
D) 150 m
E) 165 m
Let the length of the train be x m and its speed be y m/sec.   Then, x/y = 15 =&gt; y = x/15   (x + 100)/25 = x/15 =&gt; x = 150 m.   Answer:150 m
<result>D</result>
A train speeds past a pole in 15 sec and a platform 100 m long in 25 sec, its length is?