Question 645851
Let {{{ d }}} = number of Democrats
Let {{{ r }}} = number of Republicans
given:
(1) {{{ r = 2d }}}
(2) {{{ .3r + .2d = 8 }}}
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(2) {{{ 3r + 2d = 80 }}}
Substitute (1) into (2)
(2) {{{ 3*2d + 2d = 80 }}}
(2) {{{ 6d + 2d = 80 }}}
(2) {{{ 8d = 80 }}}
(2) {{{ d = 10 }}}
and, since
(1) {{{ r = 2d }}}
(1) {{{ r = 2*10 }}}
(1) {{{ r = 20 }}}
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{{{ r + d = 20 + 10 }}}
{{{ r + d = 30 }}}
There are 30 people on the committee