Question 1072588
Let {{{ a }}} = pounds of MM used
Let {{{ b }}} = pounds of RC used
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(1) {{{ a + b = 50 }}}
(2) {{{ ( 1.8a + 3.2b ) / 50 = 2.92 }}}
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(2) {{{ 1.8a + 3.2b = 2.92*50 }}}
(2) {{{ 1.8a + 3.2b = 146 }}}
(2) {{{ 18a + 32b = 1460 }}}
(2) {{{ 9a + 16b = 730 }}}
Multiply both sides of (1) by {{{ 9 }}} and
subtract (1) from (2)
(2) {{{ 9a + 16b = 730 }}}
(1) {{{ -9a - 9b = -450 }}}
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{{{ 7b = 280 }}}
{{{ b = 40 }}}
and
(1) {{{ a + b = 50 }}}
(1) {{{ a + 40 = 50 }}}
(1) {{{ a = 10 }}}
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10 pounds of MM are needed
40 pounds of RC are needed
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check:
(2) {{{ ( 1.8a + 3.2b ) / 50 = 2.92 }}}
(2) {{{ ( 1.8*10 + 3.2*40 ) / 50 = 2.92 }}}
(2) {{{ ( 18 + 128 ) / 50 = 2.92 }}}
(2) {{{ 146 = 2.92*50 }}}
(2) {{{ 146 = 146 }}}
OK