Question 1140941
b, number of bicycles
t, number of tricycles



{{{2b+3t=57}}}-----------...,with a total of 57 wheels. 


{{{b=3t-3}}}------------The number of bicycles is there less than three times the number of tricycles. 


Solving both equations for 3t, since they both have the term:
{{{57-2b=b+3}}}
-
{{{57-3=b+2b}}}
{{{54=3b}}}
{{{b=54/3}}}
{{{highlight(b=18)}}}----------eighteen bicycles


{{{highlight(7)}}}--------------------tricycles