Two trains are moving in opposite directions at 60 km/hr and 90 km/hr. Their lengths are 1.75 km and 1.10 km respectively. The time taken by the slower train to cross the faster train in seconds is? Choose the most appropriate option:  A) 48  B) 9  C) 7  D) 66  E) 15
:   Relative speed = 60 + 90= 
<gadget id="calculator">60 + 90</gadget>
<output>150</output>
150 km/hr.= 150 * 5/18 = 125/3 m/sec.   Distance covered = 1.75 + 1.10 = 2.75 km = 2750 m.   Required time = 2750 * 3/125= 
<gadget id="calculator">2750 * 3/125</gadget>
<output>66</output>
66 sec.   Answer: 66
<result>D</result>
Two trains are moving in opposite directions at 60 km/hr and 90 km/hr. Their lengths are 1.75 km and 1.10 km respectively. The time taken by the slower train to cross the faster train in seconds is?