Question 1129907
.


When I am as old as sue is now, sue will be 4 years older than I am now.
 How much older is sue than I?
~~~~~~~~~~~~~~~~~~~~~~~~~



&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;The solution by the other tutor is &nbsp;<U>TOTALLY WRONG</U>, &nbsp;so I came to fix it.


&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Below find my correct solution.



<pre>
Let y = your age now.

Let s = Sue's age now.

Let d = s - y,     (*)  the difference between Sue's age and your age.


"When I am as old as sue is now, "     (- It will happen in d years from now, and Sue will be (s + d) years old then)


sue will be 4 years older than I am now.
s + d = y + 4     (**)           <<<---===  The other tutor missed "+ d" in the left side of this equation,
                                            therefore all his further conclusions are wrong


From (**),  s - y = 4 - d = (substitute here d= s - y   from (*)) = 4 - (s-y).


Thus you have  s- y = 4 - (s-y).


Collect the terms  "(s-y)" on the left side:


2*(s-y) = 4,   


hence,  s-y = 2,


which means that Sue is 2 years older than you.     <U>ANSWER</U>
</pre>

Solved.