Question 913315
Let {{{ a }}} = the fraction of type A used
Let {{{ b }}} = the fraction of type B used
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(1) {{{ a + b = 1 }}}
(2) {{{ ( 6.5a + 4b ) = 5.75 }}}
( this equation is for 1 box )
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(2) {{{ 650a + 400b = 575 }}}
and
(1) {{{ 400a + 400b = 400 }}}
Subtract (1) from (2)
(2) {{{ 650a + 400b = 575 }}}
(1) {{{ -400a - 400b = -400 }}}
{{{ 250a = 175 }}}
{{{ a = .7 }}}
and, since
(1) {{{ a + b = 1 }}}
(1) {{{ b = .3 }}}
70% of type A is needed
30% of type B is needed