Very Logical You Can Do It
Susan drives from city A to city B. After two hours of driving she noticed that she covered 80 km and calculated that, if she continued driving at the same speed, she would end up been 15 minutes late. So she increased her speed by 10 km/hr and she arrived at city B 36 minutes earlier than she planned. Find the distance between cities A and B.
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
Assume the distance between the cities to be 'd' kms. and 't' hrs the ideal time of travel. At 40 kmph the time taken is 15 minutes more than 't'; hence. 4 0 d = t + 4 1 , Further, after 2 hrs of driving if speed is increased to 50 kmph then she arrives 36 minutes earlier or 2 + 5 0 d − 8 0 = t - 6 0 3 6 . These equations yield d = 250 km and t = 6 hrs.