Question 1034489
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A man reaches his office 40 mins late  if he walks at the rate of 3 km/hr. On the  other hand, he arrives 30 mins early 
if he walks at the rate of 4 km/hr. What is the distance between his home and his office?
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<pre>
Let L be that distance.

Then 

{{{L/3 - L/4}}} = {{{40/60 + 30/60}}},

{{{4L/12 - 3L/12}}} = {{{70/60}}}

{{{L/12}}} = {{{7/6}}},

L = {{{12*(7/6)}}} = 14 km.
</pre>

For similar problem see the lesson <A HREF=https://www.algebra.com/algebra/homework/word/travel/How-far-do-you-live-from-school.lesson>How far do you live from school?</A> in this site.