Two trains leave stations P and Q, 110km apart. Train from P to Q travels at 25Km/hr and train from Q to P at 30Km/hr. If they both start at 8 AM, they meet at:?
d = rt. the distance for one = d and the other is 110-d, the rate is 25kph and 30kph and the time is equal, so you have 2 equations, d=25(t) and 110-d = 30t. Since we know that the time is equal, if we solve each equation for t, then we can set them equal to each other and solve.
d=25(t) 110-d = 30t
d/25 = t (110-d)/30 = t, therefore
d/25 = (110-d)/30 now solve for d
30d = 25(110-d)
30d = 2750 - 25d
55d = 2750
d = 50, so the first train will travel 50 miles while the second train travels 60. At 25kph and 30kph, it will take 2 hrs before they meet up or, 10AM.