Question 1069062
.
Alvin and Geraldine are addressing invitations to their wedding. Alvin can address one every thirteen seconds and Geraldine 
can do one in 40 seconds. how long will t take them to address 140 invitations?
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<pre>
Alvin is adressing {{{1/13}}} of an invitation per second.

Geraldine is adressing {{{1/40}}} of an invitation per second.

Working together, they are addressing {{{1/13 + 1/40}}} of an invitation per second.

{{{1/13 + 1/40}}} = {{{40/(13*40) + 13/(13*40)}}} = {{{53/520}}}.

Hence, it will require {{{140/((53/520))}}} seconds to complete the job.
</pre>

Use your calculator to get the answer.



For a wide variety of solved joint-work problems with detailed explanations see the lessons

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=http://www.algebra.com/algebra/homework/Rate-of-work-word-problems/Word-problems-WORKING-TOGETHER-by-Fractions.lesson>Using Fractions to solve word problems on joint work</A>,

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=http://www.algebra.com/algebra/homework/Rate-of-work-word-problems/Solving-more-complicated-word-problems-on-joint-work.lesson>Solving more complicated word problems on joint work</A>,

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/Rate-of-work-word-problems/Selected-problems-from-the-archive-on-joint-work-word-problems.lesson>Selected joint-work word problems from the archive</A> 

in this site.


Read them and get be trained in solving joint-work problems.


Also, you have this free of charge online textbook in ALGEBRA-I in this site

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson>ALGEBRA-I - YOUR ONLINE TEXTBOOK</A>.


The referred lessons are the part of this textbook under the topic "<U>Rate of work and joint work problems</U>" of the section "<U>Word problems</U>".