Question 747390
Let {{{ a }}} = pounds of type A coffee used
Let {{{ b }}} = pounds of type B coffee used
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given:
(1) {{{ b = 2a }}}
(2) {{{ 5.95a + 4.65b = 320.25 }}}
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(2) {{{ 595a + 465b = 32025 }}}
Substitute (1) into (2)
(2) {{{ 595a + 465*2a = 32025 }}}
(2) {{{ 595a + 930a = 32025 }}}
(2) {{{ 1525a = 32025 }}}
(2) {{{ a = 21 }}}
and
(1) {{{ b = 2a }}}
(1) {{{ b = 42 }}}
21 pounds of type A coffee were used

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check:
(2) {{{ 5.95a + 4.65b = 320.25 }}}
(2) {{{ 5.95*21 + 4.65*42 = 320.25 }}}
(2) {{{ 124.95 + 195.3 = 320.25 }}}
(2) {{{ 320.25 = 320.25 }}}
OK