A train speeds past a pole in 15 seconds and a platform 100 m long in 20 seconds. Its length is?
Choices:
A) 188 m  B) 876 m  C) 251 m  D) 300 m  E) 145 m
Let the length of the train be x meters and its speed be y m/sec.   They, x / y = 15 =&gt; y = x/15   x + 100 / 20 = x / 15   x = 300 m.   Answer: 300 m
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A train speeds past a pole in 15 seconds and a platform 100 m long in 20 seconds. Its length is?