Question 1158785
.
<pre>

Every 60 seconds, E makes 3 cycles, while H makes 2 cycles; together they make 3+2 = 5 cycles each minute.


So, they need  {{{15/5}}} = 3 minutes to complete 15 cycles.    <U>ANSWER</U>
</pre>

Solved, explained and completed.


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


Such problems, &nbsp;and this one, &nbsp;in particular, &nbsp;are intended for the 3-rd - 4-th grade young students, 

who don't know equations, at all.


So, &nbsp;what I presented in my post, &nbsp;is a &nbsp;STANDARD &nbsp;method for them to solve such problems.

It is their FIRST acquaintance with the joint work problems --- therefore, the solution method should be adequate.


From this point of view, any complications in solving method (as the other tutor presents) are NOT appropriate for them. 


If you want to see many other problems, &nbsp;solved in this way, &nbsp;look into the lesson

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/Rate-of-work-word-problems/Special-joint-wok-problems-that-admit-and-require-an-alternative-solution-method.lesson>Special joint work problems that admit and require an alternative solution method</A>

in this site.