A train speeds past a pole in 15 sec and a platform 100 m long in 25 sec, its length is?  Choose the correct choice:  A) 299  B) 150  C) 267  D) 551  E) 121
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
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A train speeds past a pole in 15 sec and a platform 100 m long in 25 sec, its length is?