Question

Two trains are moving in the opposite directions on parallel tracks at the speeds of $64$ km/hr and $96$ km/hr respectively. The first train passes a telegraph post in $5$ seconds whereas the second train passes the post in $6$ seconds. Find the time taken by the trains to cross each other completely:

• A. $3$ seconds
• B. $4\frac{4}{5}$ seconds
• C. $5\frac{3}{5}$ seconds
• D. $6$ seconds

Answer 1

The correct option is C $5\frac{3}{5}$ seconds

The Length of Train Passing Through Telegraph in 5 seconds will be

$\Rightarrow L_1=64\times \frac{5}{3600}$

Similarly,

$\Rightarrow L_2=96\times \frac{6}{3600}$

Time taken by trains to completely cross each other

$\Rightarrow \frac{L_1+L_2}{V_1+V_2}$

$\Rightarrow \frac{96\times \frac{6}{3600}+64\times \frac{5}{3600}}{64+96}$

$=\frac{96\times \frac{6}{3600}+64\times \frac{5}{3600}}{160}$

$=\frac{896}{3600\times 160}Hr$

$=\frac{896}{160}Seconds=5\frac{3}{5}seconds$