A train overtakes two persons who are walking in the same direction to that of the train at 2 kmph and 4 kmph and passes them completely in 9 and 10 seconds respectively. What is the length of the train?  Pick:
A) 62 m  B) 54 m  C) 50 m  D) 55 m  E) 56 m
Explanation:   Let x is the length of the train in meter and v is its speed in kmph   x/9 = ( v-2)(10/36) ---(1)   x/10 =( v-4) (10/36) --- (2)   Dividing equation 1 with equation 2   10/9 = (v-2)/(v-4)   =&gt; 10v - 40 = 9v - 18   =&gt; v = 22   Substituting in equation 1, x/9 = 200/36 =&gt; x = 9×200/36 = 50 m   Answer: Option 50 m
<result>C</result>
A train overtakes two persons who are walking in the same direction to that of the train at 2 kmph and 4 kmph and passes them completely in 9 and 10 seconds respectively. What is the length of the train?