Question 1063181
.
I am half the age of my dad plus four but I know that my dad is eight years older than my mum and my mum gave birth to me 
at the age of twenty eight. What is my age?
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<pre>
The first equation is 

I = {{{D/2+4}}}         (1)   (I is "my age", D is dad's age)

The second equation is 

D - I = 28 + 8.   (2)   (My dad is 28+8 years older than me).


You can rewrite equations (1) and (2) in the form

2I = D + 8     (1')
D - I = 36.    (2')

From (2'), express D = 36 + I and then substitute it into (1') replacing D. You will get 

2I = (36+I) + 8  ---->  2I = I + 44   ---->  I = 44.
</pre>

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>

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>".