Question 1069073
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Sandy is 7 years younger than Mandy, in 4 years time sandy will be half Mandy's age. What are their ages presently
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<pre>
Let S be the Sandy's present age, M be that of Mandy.

S = M -7,                (1)
S + 4 = {{{(1/2)*(M+4)}}}.        (2)

Multiply eq(2) by 2 (both sides). You will get the system in this form

S = M -7,                (1')
2S + 8 = M+4.            (2')

Substitute the expression (1') for S into (2'), replacing S. You will get

2*(M-7) + 8 = M+4   --->

2M - 14 + 8 = M + 4 --->  M = 14 - 8 + 4 = 10.


<U>Answer</U>.  Mandy's present age is 10 years.  Sandy's present age is 10-7 = 3 yeras.
</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>".