Question 1020891
Let {{{ a }}} = pounds of nuts needed
Let {{{ b }}} = pounds of raisins needed
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(1) {{{ a + b = 60 }}}
(2) {{{ ( 6a + 3b ) / 60 = 4 }}}
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(2) {{{ 6a + 3b = 240 }}}
(2) {{{ 2a + b = 80 }}}
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Subtract (1) from (2)
(2) {{{ 2a + b = 80 }}}
(1) {{{ -a - b = -60 }}}
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{{{ a = 20 }}}
and
(1) {{{ a + b = 60 }}}
(1) {{{ 20 + b = 60 }}}
(1) {{{ b = 40 }}}
20 pounds of nuts are needed
40 pounds of raisins are needed
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check:
(2) {{{ ( 6a + 3b ) / 60 = 4 }}}
(2) {{{ ( 6*20 + 3*40 ) / 60 = 4 }}}
(2) {{{ ( 120 + 120 ) / 60 = 4 }}}
(2) {{{ 240 = 4*60 }}}
(2) {{{ 240 = 240 }}}
OK