Question 1130503
Let {{{ a }}} = the number of goats
Let {{{ b }}} = the number of chickens
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(1) {{{ a + b = 45 }}}
(2) {{{ 4a + 2b = 150 }}}
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(2) {{{ 2a + b = 75 }}}
Subtract (1) from (2)
{{{ a = 30 }}}
and
(1) {{{ 30 + b = 45 }}}
(1) {{{ b = 15 }}}
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There are 30 goats and 15 chickens
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check:
(2) {{{ 4*30 + 2*15 = 150 }}}
(2) {{{ 120 + 30 = 150 }}}
(2) {{{ 150 = 150 }}}
OK