one train has crossing a bridge of length 340 m in 42 sec and same train has crossing a another bridge of 500 m in 50 sec. what is the approximate speed of the train in km/hr?
Choose one
A) 60	B) 64.8	C) 72	D) 76	E) 78
length of train = l m   speed of train = v m/s then   340+l = 42v   500+l = 50v   subtract, 8v = 160   =&gt; v = 20m/s = 72 kmph   ANSWER:72
<result>C</result>
one train has crossing a bridge of length 340 m in 42 sec and same train has crossing a another bridge of 500 m in 50 sec. what is the approximate speed of the train in km/hr?