Question 1091624
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Let our clock/chronometer starts (t=0) at the moment When Narendra starts.


    Let D be the distance between the starting and ending points.

    Then  the Ramesh    rate of move is  {{{D/40}}}  linear units per minute, 
    while the Narendra  rate of move is  {{{D/60}}} linear units per minute.


The equation for Narendra position is {{{X[N](t)}}} = {{{t*(D/60)}}},       0 <= t <=60

The equation for Ramesh   position is {{{X[R](t)}}} = {{{(t-10)*(D/40)}}},  10 <= t <= 40.

The time moment when Ramesh will take to reach Narendra is determined from the equation  

{{{X[N](t)}}} = {{{X[R](t)}}},    or

{{{t*(D/60)}}} = {{{(t-10)*(D/40)}}}.


To solve it, first cancel D in both side, and then multiply both sides by 240. You will get an equivalent equation

4t = 6*(t-10)  ====>  4t = 6t - 60  ====>  2t = 60  ====>  t = {{{60/2}}} = 30.


<U>Answer</U>.  Ramesh will take Narendra in 30 minutes after Narendra started, or in 30-10 = 20 minutes after Ramesh started.
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Solved.