Question 1202710
<pre>
I think Theo's method is better.  It's easier to set up word problems when
you use more than one unknown.  Ikleyn always prefers to use one unknown if
possible.  But the system:

{{{system(b/g = 4/3,
(b-3)/(g+4) = 1/1)}}}

is more like what the words say.

Now I would cross-multiply both equations to eliminate fractions:

{{{system(3b = 4g,
b-3= g+4)}}}

Simplify the second equation:
{{{system(3b = 4g,
b= g+7)}}}

Substitute g+7 for b in the first equation:

{{{3(g+7)=4g}}}
{{{3g+21=4g}}}

{{{21=g}}}

{{{b=21+7}}}

{{{b=28}}}

21 girls, 28 boys, 21+28=49 students

Edwin</pre>