Question 1142678
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<pre>

Since Christina can make the entire job in 3 hours, working alone, she makes  {{{1/3}}}  of the job per hour.


Since Victoria can make the entire job in 5 hours, working alone, she makes  {{{1/5}}}  of the job per hour.


Working together, the two girls make  {{{1/3}}} + {{{1/5}}} of the job per hour.


Let  t be the time (in hours) for the two girls to complete the job, working together.

Then they make  {{{1/t}}}  part of the job per hour.


It gives you an equation


    {{{1/3}}} + {{{1/5}}} = {{{1/t}}}.


At this point the setup is completed: the equation is constructed, and your next step is to solve it.


For it, multiply both sides by 15t = 3*5*t to rid off the denominators. You will get


    5t + 3t = 15.


Simplify and solve for t :


    8t = 15,

    t = 15/8 = {{{1}}}{{{7/8}}} hours = 1 hour and 52.5 minutes.    <U>ANSWER</U>
</pre>

Solved and completed.


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It is a standard and typical joint work problem.


There is a wide variety of similar solved joint-work problems with detailed explanations in this site. &nbsp;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> 



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


Also, &nbsp;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>" &nbsp;of the section &nbsp;"<U>Word problems</U>".



Save the link to this online textbook together with its description


Free of charge online textbook in ALGEBRA-I
https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson


to your archive and use it when it is needed.