Question 147190
Let {{{s}}}= number of sheep
Let {{{b}}}= number of ostriches
{{{4s}}}= number of legs that sheep have
{{{2b}}}= number of legs that ostriches have
{{{2*(s + b)}}}= number of eyes sheep and ostriches together have
{{{4s + 2b = 86}}}
Divide both sides by {{{2}}}
{{{2s + b = 43}}}
and
{{{2s + 2b = 60}}}
Divide both sides by {{{2}}}
{{{s + b = 30}}}
{{{b = 30 - s}}}
Substitute this in the other equation
{{{2s + b = 43}}}
{{{2s + 30 - s = 43}}}
{{{s = 13}}}
{{{b = 30 - s}}}
{{{b = 30 - 13}}}
{{{b = 17}}}
There are 13 sheep and 17 ostriches
check:
{{{4s + 2b = 86}}}
{{{4*13 + 2*17 = 86}}}
{{{52 + 34 = 86}}}
{{{86 = 86}}}
OK