Question 264037
Let {{{p}}} = number of people
Let {{{b}}} = number of lambs (b is for baa)
They all have 1 head each, so
(1) {{{p + b = 30}}}
People have 2 legs, and lambs have 4, so
(2) {{{2p + 4b = 104}}}
Multiply both sides of (1) by {{{2}}} and
subtract from (2)
(2) {{{2p + 4b = 104}}}
(1) {{{-2p - 2b = -60}}}
{{{2b = 44}}}
{{{b = 22}}}
and, since
{{{p + b = 30}}}
{{{p = 30 - 22}}}
{{{p = 8}}}
There are 8 people and 22 lambs
check answer:
(2) {{{2p + 4b = 104}}}
{{{2*8 + 4*22 = 104}}}
{{{16 + 88 = 104}}}
{{{104 = 104}}}
OK