Question 111315
There is a 10 year span between 1990 and 1999.
For boy's soccer, The members in 1990 were {{{142 - 10*12 = 22}}}
For girls soccer, the members in 1990 were {{{120 - 10*8 = 40}}}
For football, the members in 1990 were {{{92 + 10*3 = 122}}}
The linear equations have the form y = mx + b}}}. m is the slope
and b is the 1990 membership (x=0, since I'm saying 0 is 1990)
{{{y = ((142 - 22)/10)x + 22}}}
{{{y = 12x + 22}}} for boy's soccer
{{{y = ((120 - 40)/10)x + 40}}} 
{{{y = 8x + 40}}} for girl's soccer
{{{y = ((92 - 122)/10)x + 122}}}
{{{y = -3x + 122}}} for football
{{{ graph( 600, 600, -10, 20, -10, 150,12x+22,8x+40,-3x+122) }}}
For 2001
{{{y = 12x + 22}}}
{{{y = 12*12 + 22}}}
{{{y = 166}}} students in boys soccer
{{{y = 8x + 40}}}
{{{y = 8*12 + 40}}}
{{{y = 136}}} in girls soccer
{{{y = -3x + 122}}}
{{{y = -3*12 + 122}}}
{{{y = 86}}}in football
{{{166 + 136 + 86 = 388}}}
{{{166/388 = .428}}}
{{{136/388 = .351}}}
{{{86/388 = .222}}}
Boys soccer gets 43%, girls soccer gets 35%, and football gets 22%