Question 1207363
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To add to the response from tutor @ikleyn, here is another, very different method for solving the problem.<br>
The ratio of the two speeds is 60:45 = 4:3.  Since the distances are the same, the ratio of times at the two speeds is 3:4.<br>
So 3/7 of the total time was at 60km/h and 4/7 of the time at 45km/h.<br>
(3/7) of 3 hours 30 minutes = (3/7) of 210 minutes = 3*30 minutes = 90 minutes = 1 hour 30 minutes.<br>
1 hour 30 minutes at 60km/hr is 90km.<br>
ANSWER: 90km<br>