Question 1138861
.
<pre>
Let x be the speed of A and B (the same (!) ) walking on the stationary sidewalk (in meters per second).

Then the effective speed of B on the moving sidewalk is (x+1) m/s.


The time equation is 


    {{{360/x}}} - {{{360/(x+1)}}} = 30 seconds.


Cancel the factor of 30 in both sides and then multiply both sides by x*(x+1).


    12(x+1) - 12x = x*(x+1)

    12            = x^2 + x

     x^2 + x - 12 = 0

     (x+4)*(x-3) = 0.


The roots are x= -4  and  x= 3, but only positive value x= 3 is the meaningful solution.


<U>ANSWER</U>.  The speed of A and B walking on stationary sidewalk is 3 meters per second.


<U>CHECK</U>.   {{{360/3}}} - {{{360/4}}} = 120 - 90 = 30 seconds.   ! Correct !
</pre>

Solved.


<pre>
     (Actually, it is very high speed for walking person.

      Usual speed walking is about 1 m/s, as everybody knows.

      I suspect that it would be much more realistic to have feet in this problem instead of meters !)
</pre>

--------------------


Using "time" equation is the STANDARD method of solving such problems.


To see many other similar solved problems by this method, &nbsp;look into the lessons

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/word/travel/Had-a-car-move-faster-it-would-arrive-quicker.lesson>Had a car move faster it would arrive sooner</A>

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=http://www.algebra.com/algebra/homework/word/travel/How-far-do-you-live-from-school.lesson>How far do you live from school?</A> 

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/word/travel/Earthquake-waves.lesson>Earthquake waves</A> 

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/word/travel/Time-equation-HOW-TO-write-it-and-how-to-solve-it.lesson>Time equation: HOW TO use, HOW TO write and HOW TO solve it</A> 

in this site.


From these lessons, &nbsp;learn on how to write, &nbsp;how to use and how to solve a &nbsp;"time" &nbsp;equation.