• question_answer Two trains running in opposite directions cross a man standing on the platform in 27 sec and 17 sec respectively. They cross each other in 23 sec. The ratio of their speeds is A)  1 : 2                 B)  2 : 1 C)  3 : 2                 D)  2 : 3

[c] Let the speeds of two trains be ?x? m/sec and ?y? m/sec respectively. Length of first train = 27x metres Length of second train = 17y metres $\therefore$ $\frac{27x+17y}{x+y}=23$ $\Rightarrow$ $27x+17y=23x+23y$ $\Rightarrow$ $4x=6y$ $\Rightarrow$ $\frac{x}{y}=\frac{3}{2}$ $\Rightarrow$ $x:y=3:2$