Question 692628
Note that {{{ 33.333 }}} in the problem is a percent
(1) {{{ x + y = 30 }}}
(2) {{{ .15x + .4y = 30*.333 }}}
(2) {{{ 15x + 40y = 1000 }}}
Multiply both sides of (1) by {{{ 15 }}} and
subtract (1) from (2)
(2) {{{ 15x + 40y = 1000 }}}
(1) {{{ -15x - 15y = -450 }}}
{{{ 25y = 550 }}}
{{{ y = 22 }}}
and
(1) {{{ x + y = 30 }}}
(1) {{{ x + 22 = 30 }}}
(1) {{{ x = 8 }}}
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check:
(2) {{{ .15*8 + .4*22 = 30*.333 }}}
(2) {{{ 1.2 + 8.8 = 10 }}}
(2) {{{ 10 = 10 }}}
OK