Question 801979
Let {{{ a }}} = pounds of type A coffee used
Let {{{ b }}} = pounds of type B coffee used
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(1) {{{ b = 2a }}}
(2) {{{ 4.1a + 5.9b = 461.1 }}}
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Substitute (1) into (2)
(2) {{{ 4.1a + 5.9*(2a) = 461.1 }}}
(2) {{{ 4.1a + 11.8 = 461.1 }}}
(2) {{{ 15.9a = 461.1 }}}
(2) {{{ a = 29 }}}
29 pounds of type A coffee were used
check:
(1) {{{ b = 2a }}}
(1) {{{ b = 2*29 }}}
(1) {{{ b = 58 }}}
(2) {{{ 4.1*29 + 5.9*58 = 461.1 }}}
(2) {{{ 118.9 + 342.2 = 461.1 }}}
(2) {{{ 461.1 = 461.1 }}}
OK