Question 1065447
Let {{{ a }}} = pounds of $2 candy needed
Let {{{ b }}} = pounds of $3 candy needed
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(1) {{{ a + b = 80 }}}
(2) {{{ ( 2a + 3b ) / 80 = 2.2 }}}
(2) {{{ 2a + 3b = 176 }}}
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Multiply both sides of (1) by {{{ 2 }}} and
Subtract (1) from (2)
(2) {{{ 2a + 3b = 176 }}}
(1) {{{ -2a -2b = -160 }}}
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{{{ b = 16 }}}
and
(1) {{{ a + b = 80 }}}
(1) {{{ a + 16 = 80 }}}
(1) {{{ a = 64 }}}
64 pounds of $2 candy are needed
16 pounds of $3 candy are needed
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check answer:
(2) {{{ ( 2a + 3b ) / 80 = 2.2 }}}
(2) {{{ ( 2*64 + 3*16 ) / 80 = 2.2 }}}
(2) {{{ ( 128 + 48 ) / 80 = 2.2 }}}
(2) {{{ 176/80 = 2.2 }}}
(2) {{{ 176 = 2.2*80 }}}
(2) {{{ 176 = 176 }}}
OK