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A train departs from Town X at 1:00 pm to travel to Town Y. Its average speed for the journey is 80 km/h, and it arrives at 4:00 pm. A second train departs from Town X at 1:20 pm and arrives at Town Y at 3:30 pm.
What is the average speed of the second train? Give your answer to the nearest kilometre per hour. (2 marks)
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\(\text{111 km/h}\)
\(\text{Distance between towns X and Y using first train}\)
\(\text{Time taken by first train = 3 hours}\)
\(\text{Distance}=\text{speed}\times\text{time}=80\times 2=240\ \text{km}\)
\(\text{Time taken by second train = 2 hours 10 minutes.}\)
\(\text{2 hours 10 minutes = }\dfrac{130}{60}=\dfrac{13}{6}\ \text{hours.}\)
\(\text{Find speed of second train using}\ \ s=\dfrac{d}{t}:\)
\(s=\dfrac{240}{\frac{13}{6}}=240\times \dfrac{6}{13}=110.769…\)
\(\therefore\ \text{The average speed of the second train is 111 km/h (nearest km/h).}\)