Question 794102
Let {{{ a }}} = number of times he did the laundry
Let {{{ b }}} = number of times he he mowed the lawn
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(1) {{{ .5*a + 1*b = 10.5 }}}
(2) {{{ a = b + 6 }}}
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(1) {{{ 5a + 10b = 105 }}}
and
(2) {{{ 10a - 10b = 60 }}}
Add the equations
{{{ 15a = 165 }}}
{{{ a = 11 }}}
and, since
(2) {{{ a = b + 6 }}}
(2) {{{ 11 = b + 6 }}}
(2) {{{ b = 5 }}}
He mowed the lawn 5 times
check:
(1) {{{ .5*a + 1*b = 10.5 }}}
(1) {{{ .5*11 + 1*5 = 10.5 }}}
(1) {{{ 5.5 + 5 = 10.5 }}}
(1) {{{ 10.5 = 10.5 }}}
OK