Question 563374
Let {{{ a }}} = rate for baby sitting
Let {{{ b }}} = rate for restaurant
given:
(1) {{{ 8a + 3b = 64 }}}
(2) {{{ 2a + 5b = 50 }}}
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Multiply both sides of (2) by {{{ 4 }}}
and subtract (1) from (2)
(2) {{{ 8a + 20b = 200 }}}
(1) {{{ -8a - 3b = -64 }}}
{{{ 17b = 136 }}}
{{{ b = 8 }}}
and
(2) {{{ 2a + 5b = 50 }}}
(2) {{{ 2a + 5*8 = 50 }}}
(2) {{{ 2a = 50 - 40 }}}
(2) {{{ 2a = 10 }}}
(2) {{{ a = 5 }}}
$5/hr = rate for baby sitting
$8/hr = rate for restaurant
check:
(1) {{{ 8*5 + 3*8 = 64 }}}
(1) {{{ 40 + 24 = 64 }}}
(1) {{{ 64 = 64 }}}
and
(2) {{{ 2*5 + 5*8 = 50 }}}
(2) {{{ 10 + 40 = 50 }}}
(2) {{{ 50 = 50 }}}
OK