Question 730110
Let {{{ a }}} = pounds of $1.09 candy needed
Let {{{ b }}} = pounds of $3.32 candy needed
given:
(1) {{{ a + b = 25 }}}
(2) {{{ ( 1.09a + 3.32b ) / 25 = 2.43 }}}
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(2) {{{ 109a + 332b = 243*25 }}}
(2) {{{ 109a + 332b = 6075 }}}
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Multiply both sides of (1) by {{{ 109 }}}
and subtract (1) from (2)
(2) {{{ 109a + 332b = 6075 }}}
(1) {{{ -109a - 109b = -2725 }}}
{{{ 223b = 3350 }}}
{{{ b = 15.022 }}}
15.022 pounds of $3.32 candy is needed
check:
(1) {{{ a + b = 25 }}}
(1) {{{ a + 15.022 = 25 }}}
(1) {{{ a  = 9.978 }}}
and
(2) {{{ ( 1.09a + 3.32b ) / 25 = 2.43 }}}
(2) {{{ ( 1.09*9.978 + 3.32*15.022 ) / 25 = 2.43 }}}
(2) {{{ 10.876 + 49.873 = 2.43*25 }}}
(2) {{{ 60.749 = 60.75 }}}
Close enough