Question 396085
Let {{{a}}} = number of sheep she has
Let {{{b}}} = number of ostriches she has
given:
(1) {{{2a + 2b = 60}}}
(2) {{{4a + 2b = 86}}}
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(1) {{{ a + b = 30}}}
(2) {{{ 2a + b = 43}}}
Subtract (1) from (2)
(2) {{{ 2a + b = 43}}}
(1) {{{ -a - b = -30}}}
{{{a = 13}}}
and, from (1),
{{{13 + b = 30}}}
{{{b = 17}}}
The rancher has 13 sheep and 17 ostriches