Question 1109968
.
<pre>
The condition gives you two equations

J + D = 34,                  (1)
2*(J-5) + 3*(D-5) = 61.      (2)


Simplify (2):

2J - 10 + 3D - 15 = 61,

2J + 3D = 61 + 10 + 15,

2J + 3D = 86.                (3)


From (1),  J = 34-D.  Substitute it into (3). You will get the single equation for only one unknown D:

2*(34-D) + 3D = 86,         (It is how the Substitution method works).

68 - 2D + 3D = 86  ====>  D = 86 - 68 = 18.


<U>Answer</U>.  David is 18 years old.   James is 34-18 = 16 years old.


<U>Check</U>.   2*(16-5) + 3*(18-5) = 2*11 + 3*13 = 22 + 39 = 61.
</pre>

Solved. &nbsp;&nbsp;// &nbsp;&nbsp;On the way, &nbsp;you learned on how the Substitution method works.


----------------
There is a bunch of lessons on age word problems 

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=http://www.algebra.com/algebra/homework/word/age/Age-problems-and-their-solutions.lesson>Age problems and their solutions</A>

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=http://www.algebra.com/algebra/homework/word/age/Fresh-formulation-of-a-traditional-age-problem.lesson>A fresh formulation of a traditional age problem</A>

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=http://www.algebra.com/algebra/homework/word/age/Really-intricate-age-word-problem.lesson>Really intricate age word problem</A>

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

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/word/age/Age-problems-for-mental-solution.lesson>Age problems for mental solution</A> 

in this site.


Read them and become an expert in solving age 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 online textbook under the topic "<U>Age 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.