Question 1158063
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In the half hour before the second train starts, the first train travels (60)(1/2) = 30 km.<br>
The second train catches up to the first train at a rate of (75-60)=15km/hr.<br>
The number of hours it takes the second train to catch up to the first is 30/15 = 2.<br>
ANSWER< 2 hours<br>